Momentary Loss & Regain of Power

[DavidPIL]

Hello all...I did a search on this, went back about 3 years on the forums and didn't find anything...I have a 2003 GT with just under 153,000 miles. Was driving 65-70ish for about 30 miles then the car stuttered for a brief moment. It basically felt like I hit a patch of ice (though it was 80 degrees).Later (on the way home) this happened again. Then again within 5 miles or so. This time I was going around 55ish but both times had the cruise on.I thought maybe it was the clutch slipping but I really didn't think it would only slip for a split second then regrip like that.I then tried to create the sensation myself by quickly letting off the pedal then repressing it. It felt almost exactly the same so I thought, the Cruise is going out... So, I turned the Cruise back on but kept my foot lightly on the pedal to see if I could feel it lift it did it again. I did it again but I didn't feel it lift.Later I was slowly driving through a State Park (25 mph and no cruise) and I noticed it doing it again though this time it was a bit less noticeable but when it happened, it happened 5 times randomly in maybe 3 seconds.Seriously, it feels like the tires are slipping on something but the RPMS don't quickly raise or lower (unless it happens so fast it just doesn't register.Any thoughts on this?I did recently clean out the Throttle Body at about 151,500 miles... It was quite dirty. Also at about 151,000 after a 900 mile trip while driving in my town to my house the car just shut off completely (It hasn't done that again though).it's still the original clutch so I was hoping that it was the problem (Since I had been putting off replacing it for about 3 years now). Could it be the Cruise Control? Any input would be greatly appreciated!

[lovemyraffe]

I don't think there is a problem with the cruise. Mine acts similarly when I am on a down-slope doing 70-75.

[DavidPIL]

Thanks for the response!I have narrowed it down to the clutch but I have done the several "test" I found on the forums to see if a clutch is slipping but it didn't show any signs of such.The instance it happens is so short, it seriously feels like I'm driving over a small patch of ice (or oil)Today I tried to duplicate the problem by quickly pressing and releasing the clutch real fast) with the gas pedal pressed enough to keep me at a steady 50 mph and the feeling was quite similar.In all honesty, it feels like maybe the flywheel has a depression on it or is warped in some way that only occasionally and randomly does the clutch itself lose contact. I have 153000 miles on a GT - it's about time to change the clutch anyway so I'm pricing those. I've been putting it off simply because I hate the thought of paying $400-$500 for labor alone but out of the 3 places I've gone (AAMCO, Local Tranny Shop & my usual local tire place), all their prices are basically the same. AAMCO and Tranny shop only seem to offer LUK clutches. My tire place will install whatever I bring in.

[DavidPIL]

Today it did it again... several times... all without the cruise on but this time it went from throttle open at 38 mph down to idle and didn't come back till I pressed the pedal a little harder. Could this be the Throttle Position Sensor going out? I checked of symptoms of this and found... "Bucking and jerking of the car" -As described in original post."Idle surging" - Not happening."Sudden stalling of the car engine" - As described in original post"Hesitation while the driver of the car is trying to accelerate" - I just thought I was lifting the clutch pedal too fast at times. My hesitation has been rather inconsistent, I just thought it was me or the clutch."Sudden surge in car's speed while driving on the highway" - Not on Highway but did happen today going around 30mph.It's a cheap part... and thanks to an older post by OWN4FT (http://forums.genvibe.com/zerothread?id=33198) I might as well do it, aye?Dave

[star_deceiver]

Sounds like a good place to start, check the electrical connections as well for corrosion!

[vibedrivermatt]

yup X2^ hmmmm...? have you ever cleaned your MAF sensor? there's a nice how-to on it in the maint section. dunno if that has anything to do with your prob but, might help?one time when I had an 85 audi GT coup, it was doing something similar and it turned out to be that one of the relays in the relay/fuse box was bad. That car was an automatic though. The bad relay was also causing the car to become completely bogged down, randomly at times and unable to accelerate. I dunno exactly what the relay was controlling, it was several years ago.but all that being said, at 153,000 miles, if your car still have the original clutch, I think its safe to assume that your clutch is worn and needing to be replaced. I think its possible that the symptoms you describe could maybe all be related to your clutch. The feeling of "hitting a patch or ice" could be the loss of friction between your engine and wheels, "bucking and jerking" sounds like you clutch disk getting a hold of the flywheel and then slipping off really fast in a random matter. I dunno? does any of that sound feasible?You mentioned a warped flywheel? If you go have your new clutch installed you wanna make sure to tell him/her to inspect all the teeth on your flywheel (make sure none are missing) and also to get it sent to a machine shop for resurfacing. Its my understanding that your flywheel should be resurfaced every time you replace the clutch.goodluck!

[DavidPIL]

Thanks fellow GenVibers!...Today it was pretty bad. pulled out of a drive-thru for lunch, got up to about 40ish then it started to feel like I was on a bucking bull. When almost home, it actually flat out died on me.I regularly clean the MAF when cleaning my SR intake filter and it's never really been dirty. The bucking doesn't happen on acceleration though I do notice a little jerking when starting from a dead stop, again, I always thought it was my own driving issues, The bucking seems to only happen when I finally hit a steady speed.I really have to believe it's the TPS. It looks like I'll have to take off the whole Throttle Body to get to it though. I've tried with a right angle philips bit and a philips on a bendy snake drive - I ust can't get at it at the right angle.The Repair Manual says I need to replace the Throttle Body gasket. Is this a must?

[djkeev]

Fuel pump is telling you that it is about to die.Keep your AAA up to date and go with the long distance towing option.DaveMust you replace the Throttle Body Gasket? No, but you would be unwise not to. An air leak here will cause you unspeakable grief.

[DavidPIL]

Gasket ordered.The symptoms do seem similar but they lean more toward the sensor right now. While at cruising speed with the pedal somewhat pressed, the instances of bucking is as if I release the pedal then press again. Like a connection is lose. Accelerating has been fairly solid as well as starting except for what feels like I drop the clutch too fast when going from -0- and a little at each "granny" gear change.It may be the Fuel Pump but I think I'll start cheaper first with the sensor then move on to the next thing.Autozone has a 2 yr warranted sensor for $56. Sounds like a decent price.

[DavidPIL]

Well, after replacing the sensor, I went for a drive and all was perfect... until I was just about home and for a brief moment noticed a slight loss of power. This was after a 45 minute drive. Yesterday I went out again, going about 12 minutes away and within 2 miles, the bucking began again. This time much worse and with the vehicle dieing 8-10 times. So now I move on to the Fuel Pump as djkeev suggested. I'm nervous about replacing the pump myself but I'm not sure I want to fork out a lot of money for labor when it's possible for me to do the work myself.I've researched the prices for a pump and it ranges anywhere from $56 at GM Parts Direct to $193 from Advance Auto. NAPA has a Bosch Pump for $87 with a strainer, so I guess that's where I'll go. The other option is a place like Car Stuff.com which has a Denso Pump+Filter for $133 (without filter is $131)

[star_deceiver]

There's an access panel under the back seat which makes it sooooo much easier to change then having to drop the tank (like in my old Sunfire)...$87 for a pump is a really good deal!!!!

[DavidPIL]

Job done, sorta... Still have to put the seats back but it's in and apparently working. The $87 one from NAPA is no longer available. Oh, but they had one for $256. I asked the Manufacturer's name and located the same one on Amazon.com for $62. It seemed fine other than the need to change the wire connector.It was a pain in the (removed) to disconnect the Evaporator tube. It just wouldn't disconnect so, after about 2 hours trying I had to Macgyver it.Car started fine, ran for 10 or so minutes with no problem...Will test it out on the road tomorrow.

[epcIII]

Hope it works out! I really hate 'fixing' something, going on the test drive and things go fine for a bit just to have it act up again.

[djkeev]

Quote, originally posted by DavidPIL »Job done, sorta... Still have to put the seats back but it's in and apparently working. The $87 one from NAPA is no longer available. Oh, but they had one for $256. I asked the Manufacturer's name and located the same one on Amazon.com for $62. It seemed fine other than the need to change the wire connector.It was a pain in the (removed) to disconnect the Evaporator tube. It just wouldn't disconnect so, after about 2 hours trying I had to Macgyver it.Car started fine, ran for 10 or so minutes with no problem...Will test it out on the road tomorrow.Oh please work, please work, please work, please work...... (my reputation is on the line here) Dave

[Wolfman213]

I hope this works for ya!!! Quote, originally posted by djkeev »Oh please work, please work, please work, please work...... (my reputation is on the line here) DaveHAHA, yeah esp considering you were the only person out of the group that suggested the fuel pump!

[DavidPIL]

Hey...Well, drove for about a mile then it started to chug again. Died a couple times but only when coming to a stop. I can't figure it out so maybe it's time to take it in?The only thing I've done in the past month to the car was clean the throttle body. What could I have done there to make this issue occur?It seems the warmer it is outside, the faster the symptoms come up. The day I drove it after changing the TPS, it was a cool evening. It drove for 30 - 45 minutes without incident. Today it's only 75 - 76 degrees but the sun feels hot. I just can't figure it out.Any other ideas?

[BlueCrush]

Me: Auto Problem Solving for $600.Alex: "Causes Momentary Loss & Regain of Power"Me: What is a bad Unichip? Alex: Correct!Me: Auto Problem Solving for $800. (did I win?)

[DavidPIL]

Seriously?I did just get it reprogrammed in early Spring. Had it out for almost a year because I didn't think the custom programmer did it right. (poor mileage afterward). I put it back in maybe 3 months ago?I'll pull it out now and see what happens.

[BlueCrush]

It's worth a shot. I have heard of a couple Unichips going bad over time.

[DavidPIL]

*DING* *DING* *DING*We have a winner! (for now)Well, took the Unichip out. It's a pretty quick process since I've done it a few times. Started up - didn't die but did start to act like it had Turrets... Then after about a 10 minute idle, it was smooth. Drove around for about 15 minutes and no jerky feeling or hiccups or anything.Now when I changed out the TPS, I drove around for about 30-45 minutes without an issue so this isn't the real test yet but so far-so good.As for replacing the Fuel Pump and TPS, they're things that I'm sure might go soon anyway, especially the pump. I've had a few times recently when I wasn't sure I was going to make it to the gas station and I know that's bad for the pump... so... no big loss there unless this pump goes out on me. I still think the TPS might have been the initial issue anyway because the pedal to response felt much better after.So, for now, all is well *knock on wood*... except my blood pressure, which has been sky high since yesterday Thanks to all who chimed in. It's always nice to have input and suggestions... otherwise I'd be paying $$$s just for someone to look at it. Thanks!

[BlueCrush]

Excellent! Keep us updated if all remains good.