SOLVED!! Intermittant rough engine with 4 codes P0351-P0354

[energyguy88]

Hello everyone.

I've had this 2005 Matrix since 2007 and it's been fantastic (240,000km), but now I have my first head scratcher. I hope someone here has a few ideas.

Intermittently while driving the engine will go rough for a few seconds, maybe even as long as half a minute and then go back to normal. When this happens the CEL will come on and I'll get 4 error codes ( I got a fuel economy scanner that also do error codes ). The codes that pop up are:
P0351, P0352, P0353 and P0354. This has happened at least 10 different times and everything is always the same.

My long-time trusted, independent mechanic though it might be the Engine Control Module (ECM) (also some places referred to as the PCM). So I took a chance and got a second hand unit from a wrecker ($60) and had the local dealership swap it in and reflash it ($100). I took it for a 15 minute test drive afterwards and had no issues. It looked like that might have been the source of the problem, but it turned out that my sample size was not large enough. The next day the issue popped up 3 times on a 20 minute drive.

Oh yeah, I almost forgot to mention that my Matrix was not part of the recall for ECMs

[Caretaker]

As we say on the Honda Fit boards, don't spend any money on repairs until you have fresh Denso plugs in the chambers, fresh Denso ignition coils plugging into them, and have your intake/exhaust valves regapped. In the case of our VVTi's, the first two apply. I'm sure it is time for fresh ignition coils. Oh yeah........its time to find yourself a new mechanic.

[energyguy88]

Thanks for the feedback.

I agree with you. Plugs and ignition coils don't last forever and they degrade with time. Who here will be shocked to hear me say that I still have the original plugs and coils !!!! That's almost true. A year ago I had a single coil go bad. When that failed it was a non-stop rough ride. I got the appropriate code on the scan tool (P0352) replaced the coil and have been A1 up until the recent issue.

I am clearly reading the situation which is the error codes are says I have an issue with the electrical on 1 and 2 and 3 and 4. Soooooo, one super clear possibility is that I need 4 new coils and then I'm all fixed. I'm wondering if it's not the coils but rather something that is common to the 4 coils?

Caretaker.... have you heard of anyone who had the same issue? Getting all 4 codes all at once .... intermittently ?

[jolt]

What all four coils have in common, other then the ECM, is the wiring. Check the continuity of all the wires going from the ECM to the coils. Be sure to check your ground wire in the coil wire loom. The wire will be located grounding on the valve cover or the upper cylinder head by a bolt. Make sure that the wire terminal is crimped on the ground wire and has good continuity to the wire. If the ground wire is not grounded good, it will make all four coils act up. Ground wires are colored white with a black stripe on these cars most of the time. General rule of wiring: You can never have a wire that is to good of a ground wire and never have to many ground wires.

If you have not changed your spark plugs, do it. When you have the spark plugs out, check your coils for any damage like cracks or carbon arcing. Check that you do not have oil in the spark plug wells. The oil can short the coils and is cause by leaking valve cover gasket. If you need to replace the valve cover gasket, check your valve clearances while you have the valve cover off. When replacing spark plug and/or coils, use only Denso brand as that is the OEM brand. These cars can get picky about the electrical items you use and you are better off sticking with the OEM part for the longest service life. Use dielectric grease on the coil to spark plug and on the electrical connections. This will seal out any moisture and prevent corrosion, making for a better long term connection. The grease is non-conductive and can be found in auto parts stores. Here is a link: https://www.amazon.com/Permatex-22058-D ... 000AL8VD2/

[Caretaker]

While I can't comment on codes since I don't get wrapped up in them as they often lead mechanics astray and drain your wallet in the process, I would always stick with the basics as I pointed out in the original note. Replacing one ignition coil at a time is not recommended. I know we are all strapped for $$, but when it comes to Japanese engines it's "all the plugs out and all the ignition coils out at the same time." Honda engines in particular are known for torturing their owners when they sense cheaper parts being put in or a "one off" solution being performed (ie: one plug or coil at a time). Again, don't ever pay for any repairs nor entertain any theories until all four plugs and ignition coils are replaced with Denso. After that, then you can start worrying about codes and conspiracy theories regarding your car's troubles. If this was a Jeep-Chrysler board, then I'd throw out everything I just said, but if you have a Honda or Toyota engine, stick with the basics; their engines tend to not develop gremlin issues like domestic products do.

[energyguy88]

Thanks Jolt and Caretaker.

You've both given me more to consider. I hope to have time to look at things soon, but I got other burgers on the front burner at the moment that are starting to smoke! Luckily I have loaner wheels for now so I don't have to drive the currently troubled Matrix.

My first step will be to check/clean the grounding connections as it seems like this could be the source of the issue or a contributing factor.

The valve cover gasket is leaking a little and I am still using the original plugs and coils. Those parts have served me well and so it seems appropriate to give them a retirement. I'll gear up to replace the whole lot plus the PCV valve and also check/adjust valve clearance.

I'll give an update on things when I make some progress.

Thanks again you guys!

[Bookworm]

If you're going to do all that, I'd suggest paying a very small additional amount of money, and do the following.

Pull the radiator fan (it takes seconds, really) for the extra room, drape a blanket over the radiator, and replace:

Intake manifold gasket
Throttle body gasket(s).
Air filter

as well as clean the mass air flow sensor.

You might even replace the thermostat, since you'll have everything nicely exposed.

[energyguy88]

It appears that the issue is solved !!!!!!

I was feeling I could be out of my depth and so I did some asking around locally to try and find a better than average car guy with electrical/control stuff.

The new guy he was able to pin-point the issue to the "NEW" coil on plug that I had put in 2 years ago. He figures that it was shorting out internally and was not able to get the plug to spark. He replaced that "after market" COP with a DENSO unit and he also put in all new DENSO spark plugs.

It's been a week and so far everything is back to normal. Engine runs smooth, no CEL and no OBD codes. Thumbs up !!!!

This has been a good reminder to stick with the DENSO parts on the Matrix.

I'm still planning to do some other maintenance items myself in the coming weeks that I've already mentioned.

Thanks for the pointers everyone !!!