Hey Guys,

I've been an off and on Lurker since I purchased my Z24 back in 2000. I was searching the forums about my misfire problem, and there seemed to be a lot of knowledgeable people responding. I have a friend who is a mechanic coming over this upcoming week to check out my car, and was hoping some people could help me point him in the right direction.

About a week ago, I was heading out to a friend's place with my Cavalier. I had no power as I pulled out of the driveway and accelerated. At first I thought I just wasn't getting any traction due to it snowing out. (First snow of the season, cheap tires). About two blocks a way, I noticed that my car was shaking. Shortly after that, my "Check Engine Light" started flashing. As I pulled up to a stop sign, my car stalled. I was able to start it again, but it cranked for a bit. I then put the car in reverse, turned around, and limped back to my house with it. When I got back to my house, I could not make it up the driveway. I am not sure if this was due to the loss of power, the snow, or a combination of both.

With the car still running in the driveway, I got out and it smelled awful. Best way I could describe it is to say it smelled like an epic fart. It also smelled like something was burning. I popped the hood, but did not see any smoke/steam etc. The engine was shaking though. The back of the car also sounded awful. By sounded awful, I guess I could describe it as a rough idle? I did not hear anything that sounded like knocking or pieces of metal hitting into each other.

I have an OBD II scanner that I bought from NAPA. When I scanned it, I had a P0300 code, which indicated a misfire. I don't think it specified which cylinder was doing the misfire though. I also had some O2 Sensor related codes, but I forget which ones they were. If you need them, I can scan again.

In true hindsight is 20/20 fashion, the day before this happened, I drove my car around 100 miles locally. There were a few times where I noticed that fart smell I mentioned above, but it was not constant. I was also driving past some industrial areas, which is where I thought the smell was probably coming from. During this entire time, the car ran normally.

The car has been parked since the day last week that the "Check Engine Light" started flashing. (I have another vehicle I can drive.) The car itself is a stock automatic, with just under, 209,000 miles on the engine.

Any suggestions/advice/comments/etc would be appreciated.

Thanks

pull the coil pack housing and check the springs on the inside. Also have your ignition control module checked. If either look bad or test bad, then replace.

I would also check the vaccum hose on the map sensor (which is on the side of the throttle body). It could be cracked. If so replace it.

if that is good then check the spark plug boots for cracks, then the coils, and even the housing.



FU Tuning

The "fart" smell may be the cat going bad also if your able, take the exhaust loose at the manifold down pipe (not the head) start it and see if it runs better it will be loud so try not to tick off the neighbors. If it seems better try replacing the converter. If the engine can't exhale it will cause a rough idle and misfire.

I have a 2001 Z24 with 2.4 L engine 121K miles and have nearly the same problem.
It ran great until I fixed a heater hose quick disconnect leak and now except for the "fart smell" I have the same symptoms as the OP but NO codes at all.
I've checked the coils with an ohmmeter, they read exactly the same.
Plugs cleaned, boots look excellent, ignition housing clean, no tracks. no corrosion etc, anywhere.
Fuel pressure is good, filter good.
Idle is perfect, but any throttle application and it bogs down with almost no power, starts missing and has lots of intake air noise.
Any suggestions?
Hopefully you will forgive me for hijacking the thread.

Steve

Steve B: Your problem sounds a LOT like the problem I had on my 1996 2.4L Cavalier. Like you, I tried to diagnose the problem with an ohmmeter, but for my problem an ohmmeter is not capable of diagnosis because the problem is caused by high-voltage arcing. So the problem-causing short-circuit (which steals the high-voltage pulse before it gets to your spark plug) doesn't flow through wires that you're testing. Electricity arcs through concealed cracks in the plastic of the ignition coil house, like lightning arcs through the air. A low-voltage ohmmeter can't create that high-voltage arc and so the wires inside the ignition coil housing seems to be just fine (as far as the ohmmeter can tell.)

I recommend that you read the thread at the following link-- especially the later posts that I wrote (starting at about the 8th post where I wrote "Solved!") and extending through my remaining posts in that thread. The bottom line is that, if you have the same problem that I had, then (unless your time is worth nothing) you should probably replace the ignition coil housing, the coils, the spark plugs, and the coil-on-plug insulator boots. ~$80 total. Easy job. Maybe 30 minutes-- even for a novice if you follow the step-by-step instructions that I posted.

http://www.j-body.org/forums/read.php?f=11&i=167426&t=165871#167426