Rough Idle ( LONG ) **UPDATED 10-29-22**

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cptnsolo77
Posts: 1645
Joined: Sun Jul 29, 2007 4:05 am

Rough Idle ( LONG ) **UPDATED 10-29-22**

Post by cptnsolo77 »

I have been tracing a vibration in idle for longer than I even care to admit. During warm up ( until operating temp ) it idles rough. After it warms up, it get better but still not where I know it should be. I know the 1ZZ isnt the smoothest by design but Heres my story.

-Replaced all engine/trans mounts twice and I will explain why: Early 2020 I replaced the front and side mounts myself. The rear mount ( firewall side ) looked to be too much to handle so I decided to have a mechanic take care of that one. COVID came in and I did not feel comfortale taking it to a shop...so for 9 months the car vibrated terribly and violenty. I found a mechanic that would come to my house so it will be safe repair pandemic wise. He replaced the rear mount and it was shot, completely torn. Practically driving with 3 mounts. After having that last mount replaced, I still had this vibration at idle. Being that I drove with a mix of new/old mounts....I suspected after 10,000 miles maybe I prematurely worn the new ones. So I did a little experiment: I replaced one mount at a time and see if the issue improved...and it did. As I replaced each mount, the vibration became less and less. So its looking good here right ? When I had the rear mount left and still just a bit of vibration, I thought that this last mount would finally do the trick. It did not change anything. So I guess I can rule out engine/trans mounts now LOL. The mounts are all Toyota OEM.

-I do have a PO 442. Replaced both gas caps, purge and vent evap solenoids had a mechanic do a smoke test. He couldnt find any leaks, he suspects the charcoal canister maybe leaking internally. In my opinion if the leak is that small, it wouldnt contribute to THAT rough an idle. I could be wrong though.

-Replaced all plugs in the last month, the coils are Denso units that are 2 years old from a missfire I had, so replaced all 4.

-Fan assembly. The other day I noticed when I had the key on/ignition off there was a vibration in the steering wheel. Weird because the engine isnt running. The fan was on high ( car was just driven and I was ready to start it again ) I did this a 2 more times and noticed the same issue. The fan seem to have excessive vibration on high speed. When the car was off I turned the fan blade by hand and just before it stopped i heard a small squeal. My logic...the bearings are worn, and putting a electrical load and causing a little vibration. New fan assembly and no change. I also noticed the vibration was more apparent when the AC condenser fan kicked in on high and that also led me to beleive the fan assembly may be causing my issue. That leads me to the next thing....IAC valve. Im also experiencing a hard start when the car has been sitting after it has been driven. It starts up fine in the morning.

-The IAC and throttle body was cleaned 3 years ago. Aprox. 25K miles ago. This was the 2nd time it has been cleaned. I cant see it being that dirty that it would cause rough idle. Even at the dirtiest it never idled this way. Unless the IAC is just faulty. I do have 272,000 miles now. With the AC on it does idle about 800 RPMS and the idle doesnt dip with a load from the AC. So its seems the IAC is working correctly. I understand that the IAC is supposed to bump up the RPMs when the AC condenser fan kicks in, but my RPMs are steady at 800 and not fluctuating. Again....I can be wrong, thats why I havent fixed it LOL.

Any ideas ? Im stumped. Im starting to think I did some kind of damage driving with a bad motor mount for so long.

****UPDATE 9-9-2021****

CEL gave me a PO303 ( misfire cylinder #3 ) and PO420 ( Catalyst System Efficiency Below Threshold (Bank 1) It would also stumble a little into 2nd and 3rd under hard throttle. I had a spare coil and swapped it out, cleared the code and its been 2 weeks and the 303 and 420 code have not returned. When I replaced the coil I did a little under hood inspection and found the center bolt for the front engine mount completely loose. I tightened it up and went for a drive. Car drives MUCH better, throttle response is improved and the car doesnt feel like its struggling anymore, and not stumbling into 2nd and 3rd. Shifts are very crisp. It still idles a little rough when cold and when the AC condenser fan is on HI, but its improved.

SOOOOO.....Last week I bought a can of Cataclean ( yeah I know :lol: ) in fear of the PO420 code and gave it a shot. Followed the directions and ran the Vibe HARD. Guess what ? The idle improved, maybe a clogged injector ? Again idle is not perfect but better. Slowly but surely here.

At this point I feel like taking shots in the dark, so I decided to pickup a new MAF sensor. To my surprise, it did smooth out the idle ( old one was cleaned to rule that out ) I even swapped the old one out twice to compare between new and old. New MAF it seems to run better. Have no clue why....

The only time where I feel it idles rough is when the engine is below operating temp OR when the AC condenser fan kicks in on HI. When the fan is on LOW speed I really cant tell the difference now. It used to idle rough in HI and LOW speed.

So after 1 coil, loose engine mount, new MAF sensor and a bottle of Cataclean the Vibe is idles WAY better. Even when I lightly feather the throttle around 50 MPH it feels very smooth. I still have a bit of vibration at idle when the AC fan is on HIGH but its tolerable now. Im begining to wonder if I have another coil that hasnt thrown a code yet, that may be starting to go. I might replace the coils one at a time and see what happens. Driving today I noticed a little stumble when I give it a light throttle coming off a traffic light around 1200 RPMs. Sign of another bad coil ? Either way I feel like Im VERY close to solving my idle issue.....WHEW ! It has been a LONG journey ! :lol: :roll:

*****UPDATE 10-29-22****

Turns out I have low compression likely due to gummed up oil control rings, so I gave a it a shot with BG EPR, valvoline max life and marvel mystery oil. Heres my story:

1st treatment of BG EPR and MOA oil additive in Feb:

-smoother idle. Its proven because my door panel rattle has gone away. Also doesnt vibrate as much when the AC fan kicks in on high.
-smoother throttle response at 40 -50 MPH. On light throttle the pedal feels light and less resistance.
-Shifts are smoother.
-Increased MPGs. Normally I get 75 miles ( at best ) at the 1/4 tank mark after a fill up. Now 93-94 at the 1/4 tank ( after fillup ) for 2 weeks in a row. I can SOMETIMES get that number without the AC running. 93-94 miles has been with the AC ON. These numbers have been consutent for a month.
-Gained power. Car doesnt feel as sluggish as before. Almost like it breathing better.
-Oil consumption: SAME. Still burns 1 QT per 1000 miles. It sure drives better though. That alone is worth it.

2nd Treatment of BG EPR and MOA oil additive, 300 miles later:

- smoother idle from the 1st treatment
- smoother shifts from 1st treatment
- engine feels like it picked up a bit more power
- smoother throttle response at 40 -50 MPH from the 1st treatment. On light throttle the pedal feels light and less resistance a bit more than 1st treatment
- definitely worth doing a 2nd treatment
- Quieted down my cold start rattle. I beleive its the VVT rattle on cold starts.
- Oil consumption: SAME. Still burns 1 QT per 1000 miles.

Switched to Valvoline Max Life Synth Blend ( highly recommended on Bob is the Oil guy and IS the gold standard of high mileage oils on this site ) and 1 QT of Marvel Mystery Oil in May. I was using Super Tech High Mileage synth Blend

- Immediately felt smoother after the oil change
- Idle has gradually become smoother as the months went by. I had a rattle that was behind the dash that only went away after the car warmed up. Doesnt rattle anymore even when cold.
- Increase in power, but not 100 percent
- Oil changes were done 2000 -3000 miles apart and have done 2 oil changes with valvoline oil and marvel mystery oil.
- Oil consumption: Now I am burning 1 QT every 1400 miles and of October compared to 1 QT every 1000. Im shocked, didnt expect any changes. This was my last resort to breathe some life back into the engine. Between BG EPR, Valvoline Max Life, Marvel Mystery Oil, Short oil change intervals I have decreased my oil consumption. Most likely I loosened up sludge buildup around the oil control piston rings.
Last edited by cptnsolo77 on Tue Nov 01, 2022 9:36 am, edited 7 times in total.
* 2003 Vibe Auto Satellite Silver w / Moons & Tunes
* Kenwood Excelon KDC-X597
* Polk DB651-Speakers
* Soundproofcow Roadblock R sound deadening in all doors
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joatmon
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Re: Rough Idle ( LONG )

Post by joatmon »

I can't be of much help. The matrix manual offers these possible causes for a rough idle
1. ISC valve circuit
2. Injector
3. Ignition coil (w/ Igniter) circuit
4. Compression
5. Fuel pump control circuit
6. Back up power source circuit
My second vibe constantly threw P044X codes, related to evap control, I assumed a vacuum leak somewhere, but never noticed a resulting rough idle. Never solved it, just kept the scangauge connected to reset the CEL when it came up
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cptnsolo77
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Re: Rough Idle ( LONG )

Post by cptnsolo77 »

Thx for the help anyway. My next step was going to clean the throttle body and MAF ( even thought I doubt thats the issue but you never know ) from there its the IAC. After that I dont know, I will probably swap out each coil with a good spare I have and see how it drives. I just threw in some BG fuel cleaner ( scotty kilmer recomended ) It seems a little better under throttle. I have the torque app and im going to check what the RPMs are before and after the AC is on....maybe its not raising the idle high enough. Whatever it is, it cant be that complicated a fix. We shall see..... :lol:
* 2003 Vibe Auto Satellite Silver w / Moons & Tunes
* Kenwood Excelon KDC-X597
* Polk DB651-Speakers
* Soundproofcow Roadblock R sound deadening in all doors
* Drop In K & N Filter
* NGK Iridium IX Plugs
* 27 MPG City/Highway with AC on
jolt
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Re: Rough Idle ( LONG )

Post by jolt »

I would check the compression on each cylinder. If you have a mechanical issue none of these other things are going to fix it.

Of coarse a small vacuum leak at a intake manifold runner could cause an idle issue. You could try to pinch off one vacuum hose at a time to see if it effects the idle. Or just change out the intake gasket to cross that off the list as I would think that the gasket was changed out sometime in the past but you never know.

With that many miles on it, it could be a bad fuel injector. The injectors do wear out and the spray pattern goes bad. The cars ECU can check the injectors electrical but not the mechanical spray pattern. Since most gasoline injectors are not rebuild-able, most injector shops do not test them. You could buy one injector and swap it one at a time with the old injectors and see if the idle improves.

Pull the valve cover and check the valve clearances, look the valve train over for any wear. Turn the engine over and watch to make sure all the valves are moving their full range of travel. A bad camshaft lobe, rocker arm, valve spring could cause idle issues and would be very odd but with that many miles, you just never know. These things can also effect the compression so this could be looping back to my first item here.
cptnsolo77
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Re: Rough Idle ( LONG )

Post by cptnsolo77 »

I had a mechanic do a smoke test and he couldnt find anything. I have 21 inches of engine vac ( via the torque app ) so the engine seems pretty healthy from that point of view. I didnt do a compression test and you may be on to something. The intake manifold gasket was changed back in 2013 :lol: :lol: and was replaced with the orange one...but you never know. Maybe I will check the manifold bolts, maybe they came a little loose from all this vibration ? I was thinking a bad injector as well. I threw in some BG fuel cleaner and it seemed to help a little. This is one is definitely frustrating. The only other issue that the Vibe has given me a hard time with was low idle that eneded up being a dirty IAC. Tracing that issue was a walk in the park compared to this one. I know im at 274,000 but I know she has a lot left in her.....and I dont want a car payment :roll: Thanks for the advice though, any help is appreciated ! 8-)
* 2003 Vibe Auto Satellite Silver w / Moons & Tunes
* Kenwood Excelon KDC-X597
* Polk DB651-Speakers
* Soundproofcow Roadblock R sound deadening in all doors
* Drop In K & N Filter
* NGK Iridium IX Plugs
* 27 MPG City/Highway with AC on
jolt
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Re: Rough Idle ( LONG )

Post by jolt »

Hi cptnsolo77,

Did you try pinching off different vacuum lines to see if that effected the idle? If a vacuum line is hooked to a intake manifold runner, and not to the plenum, a vacuum leak can cause that runners cylinder to run lean and miss. This can cause a rough idle condition.

Has the PCV valve been changed?
dale321
Posts: 14
Joined: Tue May 04, 2021 8:06 pm

Re: Rough Idle ( LONG )

Post by dale321 »

cptnsolo77 wrote: Fri May 28, 2021 12:56 pm Thx for the help anyway. My next step was going to clean the throttle body and MAF ( even thought I doubt thats the issue but you never know ) from there its the IAC. After that I dont know, I will probably swap out each coil with a good spare I have and see how it drives. I just threw in some BG fuel cleaner ( scotty kilmer recomended ) It seems a little better under throttle. I have the torque app and im going to check what the RPMs are before and after the AC is on....maybe its not raising the idle high enough. Whatever it is, it cant be that complicated a fix. We shall see..... :lol:
I run the torque pro all the time - BG ? - i watch alot of scotty too , he has good advice from his experience -
on my08, rpms at idle (after warmup ) run between 600 and 700 .. with a/c on this bumps to 700-800 approximately . One thing torque doenst pickup is the tranny temp .. i would really like to monitor that .. i see just about every other thing including for and aft CAT temp /O2 sensors .. but no tranny temp .. even on mine with less than 40k miles .. idle without a/c has more vibration than with the a/c on .. the hotter the water temp is the slower the idle (until electrical load like radiator fans kick on) and the more the vibration ..
zbyers
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Re: Rough Idle ( LONG )

Post by zbyers »

dale321 wrote: Thu Jun 10, 2021 8:32 pmOne thing torque doenst pickup is the tranny temp .. i would really like to monitor that .. i see just about every other thing including for and aft CAT temp /O2 sensors .. but no tranny temp .. even on mine with less than 40k miles .. idle without a/c has more vibration than with the a/c on .. the hotter the water temp is the slower the idle (until electrical load like radiator fans kick on) and the more the vibration ..
There is no temp sensor on the transmission to measure it.

It is normal for idle to be slightly higher with AC/heat on.

It is normal for idle to drop as the engine warms up.
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cptnsolo77
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Re: Rough Idle ( LONG )

Post by cptnsolo77 »

jolt wrote: Thu Jun 10, 2021 6:58 pm Hi cptnsolo77,

Did you try pinching off different vacuum lines to see if that effected the idle? If a vacuum line is hooked to a intake manifold runner, and not to the plenum, a vacuum leak can cause that runners cylinder to run lean and miss. This can cause a rough idle condition.

Has the PCV valve been changed?
I can check but I havent done any work on the car that required disconnecting vaccum lines. Yes the PVC was changed in 2018. I routinely change my oil so I cant see it sticking, but you never know.
* 2003 Vibe Auto Satellite Silver w / Moons & Tunes
* Kenwood Excelon KDC-X597
* Polk DB651-Speakers
* Soundproofcow Roadblock R sound deadening in all doors
* Drop In K & N Filter
* NGK Iridium IX Plugs
* 27 MPG City/Highway with AC on
cptnsolo77
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Joined: Sun Jul 29, 2007 4:05 am

Re: Rough Idle ( LONG )

Post by cptnsolo77 »

dale321 wrote: Thu Jun 10, 2021 8:32 pm
cptnsolo77 wrote: Fri May 28, 2021 12:56 pm Thx for the help anyway. My next step was going to clean the throttle body and MAF ( even thought I doubt thats the issue but you never know ) from there its the IAC. After that I dont know, I will probably swap out each coil with a good spare I have and see how it drives. I just threw in some BG fuel cleaner ( scotty kilmer recomended ) It seems a little better under throttle. I have the torque app and im going to check what the RPMs are before and after the AC is on....maybe its not raising the idle high enough. Whatever it is, it cant be that complicated a fix. We shall see..... :lol:
I run the torque pro all the time - BG ? - i watch alot of scotty too , he has good advice from his experience -
on my08, rpms at idle (after warmup ) run between 600 and 700 .. with a/c on this bumps to 700-800 approximately . One thing torque doenst pickup is the tranny temp .. i would really like to monitor that .. i see just about every other thing including for and aft CAT temp /O2 sensors .. but no tranny temp .. even on mine with less than 40k miles .. idle without a/c has more vibration than with the a/c on .. the hotter the water temp is the slower the idle (until electrical load like radiator fans kick on) and the more the vibration ..
800 RPMs is what it idles at when the AC is on, so it seems like the IACV is functioning. Its WEIRD....lately has been idling smoother. The fuel cleaner didnt too much honestly and that was 3 weeks ago. About 2 weeks ago I was driving and it seemed to idle better, but i havent done anything. I dont think it would have been the fuel cleaner because I already went through the fuel cleaner and refilled the tank. The weather has definitely been very hot....making me think the issue is temperature related. BTW I replaced the engine temp control sensor too. I replaced it when when I was trying to diagnose a hard start when hot issue, that ended up being a bad coil :lol:

Me stumped :lol:
* 2003 Vibe Auto Satellite Silver w / Moons & Tunes
* Kenwood Excelon KDC-X597
* Polk DB651-Speakers
* Soundproofcow Roadblock R sound deadening in all doors
* Drop In K & N Filter
* NGK Iridium IX Plugs
* 27 MPG City/Highway with AC on
cptnsolo77
Posts: 1645
Joined: Sun Jul 29, 2007 4:05 am

Re: Rough Idle ( LONG )

Post by cptnsolo77 »

cptnsolo77 wrote: Fri Jun 11, 2021 6:44 pm
dale321 wrote: Thu Jun 10, 2021 8:32 pm
cptnsolo77 wrote: Fri May 28, 2021 12:56 pm Thx for the help anyway. My next step was going to clean the throttle body and MAF ( even thought I doubt thats the issue but you never know ) from there its the IAC. After that I dont know, I will probably swap out each coil with a good spare I have and see how it drives. I just threw in some BG fuel cleaner ( scotty kilmer recomended ) It seems a little better under throttle. I have the torque app and im going to check what the RPMs are before and after the AC is on....maybe its not raising the idle high enough. Whatever it is, it cant be that complicated a fix. We shall see..... :lol:
I run the torque pro all the time - BG ? - i watch alot of scotty too , he has good advice from his experience -
on my08, rpms at idle (after warmup ) run between 600 and 700 .. with a/c on this bumps to 700-800 approximately . One thing torque doenst pickup is the tranny temp .. i would really like to monitor that .. i see just about every other thing including for and aft CAT temp /O2 sensors .. but no tranny temp .. even on mine with less than 40k miles .. idle without a/c has more vibration than with the a/c on .. the hotter the water temp is the slower the idle (until electrical load like radiator fans kick on) and the more the vibration ..
800 RPMs is what it idles at when the AC is on, so it seems like the IACV is functioning. Its WEIRD....lately has been idling smoother. The fuel cleaner didnt too much honestly and that was 3 weeks ago. About 2 weeks ago I was driving and it seemed to idle better, but i havent done anything. I dont think it would have been the fuel cleaner because I already went through the fuel cleaner and refilled the tank. The weather has definitely been very hot....making me think the issue is temperature related. BTW I replaced the engine temp control sensor too. I replaced it when when I was trying to diagnose a hard start when hot issue, that ended up being a bad coil :lol:

Me stumped :lol:
* 2003 Vibe Auto Satellite Silver w / Moons & Tunes
* Kenwood Excelon KDC-X597
* Polk DB651-Speakers
* Soundproofcow Roadblock R sound deadening in all doors
* Drop In K & N Filter
* NGK Iridium IX Plugs
* 27 MPG City/Highway with AC on
dale321
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Re: Rough Idle ( LONG ), my vaccuum

Post by dale321 »

BTW: i was watching the vaccuum closely and I'm getting about 23-24at idle , drops a little with the A/C on .. and on kind of a downshift a 27.9 psi was recorded. Engine is prob. in it's prime with less than 40k miles on it ..
jolt
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Re: Rough Idle ( LONG )

Post by jolt »

cptnsolo77 wrote: Fri Jun 11, 2021 6:31 pm
jolt wrote: Thu Jun 10, 2021 6:58 pm Hi cptnsolo77,

Did you try pinching off different vacuum lines to see if that effected the idle? If a vacuum line is hooked to a intake manifold runner, and not to the plenum, a vacuum leak can cause that runners cylinder to run lean and miss. This can cause a rough idle condition.

Has the PCV valve been changed?
I can check but I havent done any work on the car that required disconnecting vaccum lines. Yes the PVC was changed in 2018. I routinely change my oil so I cant see it sticking, but you never know.
You do not remove the vacuum lines, just pinch them off one by one. These work well for most lines: https://www.amazon.com/Lisle-22850-Hose ... 572&sr=8-5
jolt
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Re: Rough Idle ( LONG )

Post by jolt »

Standard engine vacuum is measured in inches of mercury and not pounds per square inch (psi). It is a vacuum, not a pressure, which is relative to where you are in elevation.
cptnsolo77
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Re: Rough Idle ( LONG ) **UPDATE**

Post by cptnsolo77 »

***Bump***
* 2003 Vibe Auto Satellite Silver w / Moons & Tunes
* Kenwood Excelon KDC-X597
* Polk DB651-Speakers
* Soundproofcow Roadblock R sound deadening in all doors
* Drop In K & N Filter
* NGK Iridium IX Plugs
* 27 MPG City/Highway with AC on
cptnsolo77
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Re: Rough Idle ( LONG ) **UPDATED 10-29-22**

Post by cptnsolo77 »

Updated
* 2003 Vibe Auto Satellite Silver w / Moons & Tunes
* Kenwood Excelon KDC-X597
* Polk DB651-Speakers
* Soundproofcow Roadblock R sound deadening in all doors
* Drop In K & N Filter
* NGK Iridium IX Plugs
* 27 MPG City/Highway with AC on
SSizler
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Re: Rough Idle ( LONG ) **UPDATED 10-29-22**

Post by SSizler »

Thanks for the awesome update and detailed information!
I have been a fan of Marvel Mystery Oil for many years.
Do you ever add it to your fuel tank after filling up?
I often add 4 ounces after filling the tank to assist with top end lubrication and cleaning.
2003 Vibe Base / Frosty Mono / Moon & Tunes / Auto / 206k mi / Total Loss 1-23
2006 Vibe AWD / Lava Mono / Loaded w/Leather and Sport Pkg / 150k mi
Many other 2 & 4 wheel toys :mrgreen:
40 years with a wonderful woman / 2 adult kids
cptnsolo77
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Re: Rough Idle ( LONG ) **UPDATED 10-29-22**

Post by cptnsolo77 »

Its funny because I have known about marvel mystery oil for the longest time, but thought it was snake oil. No lie....EACH time I had done a oil change with a full quart of the marvel oil it feels smoother than the last oil change. I just did my 3rd oil change with marvel oil/valvoline and it didnt disapoint...slightly smoother idle than the last oil change. Its definitely doing SOMETHING. Yes....I just started using it in the tank after every fill. It smoothed the idle a bit too. I was going to buy some BG 44K fuel cleaner but forgot that you can use marvel mystery oil in the tank too. I only have 4 quarts of it :lol:
* 2003 Vibe Auto Satellite Silver w / Moons & Tunes
* Kenwood Excelon KDC-X597
* Polk DB651-Speakers
* Soundproofcow Roadblock R sound deadening in all doors
* Drop In K & N Filter
* NGK Iridium IX Plugs
* 27 MPG City/Highway with AC on
lexicon
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Re: Rough Idle ( LONG ) **UPDATED 10-29-22**

Post by lexicon »

Cptnsolo77
You mentioned low compression, did you do a before and after compression test to see if the compression improved?

Glad you solved your longstanding problem.

I will try a can of BG EPR in my engine oil prior to my next oil change soon.

I posted previously about my experience w Royal Purple Max clean and I am getting about 28 mpg , before this it had dropped to 24 mpg over a several month period. So, fuel injection cleaner does work
Also, I concur, Since i switched to Mobile one High Mileage synthetic and my cold start VVT-i rattle went away and has not come back....( I had been using Mobil One synthetic non-High Mileage for years.... )
Thanks for your post, I will give BG EPR a shot . Additives do work. I have 238k miles on my Vibe
2005 VibeAutomaticStockNon AWD125 hp model
cptnsolo77
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Re: Rough Idle ( LONG ) **UPDATED 10-29-22**

Post by cptnsolo77 »

No I havent done a compression test after. The reduction in oil consumption and smoother idle was enough for me. However, it didnt completely resolve my problem. It still idles a bit rough cold, but then smooths out after it reached operation temp...BUT that span of time where it smooths out is much shorter now. Its a night a day difference, but not 100 percent by all means, and not driving like it was new :lol: Its acceptable for its age and still have some work to do. Im not going to lie, I am very happy for the reduction of oil consumption. I thought Vibe would have died by now, let alone run better. Just trying to buy time until the used car prices come down. So far its working :lol:
* 2003 Vibe Auto Satellite Silver w / Moons & Tunes
* Kenwood Excelon KDC-X597
* Polk DB651-Speakers
* Soundproofcow Roadblock R sound deadening in all doors
* Drop In K & N Filter
* NGK Iridium IX Plugs
* 27 MPG City/Highway with AC on
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