The coil pack on my 01 2.4L took a dump on me a little over a week ago. Got it towed to the dealer and they replaced the coil. (Paid $311 bucks!!! Thieves!)
Since then, my CEL has been on with a p0420 code. I've been reading the current thread about the problem however...
Yesterday the car seems to have started misfiring again. It only happens if the RPM's are low and I hit the gas. I first noticed it in 5th gear going about 45 and having to hit the gas a little to go up a hill. I can make the car misfire in any gear. It only happens when the RPM's are low and you give it gas. Once the RPM's go up, the misfire disappears. The bucks pretty hard, just like it did when the ICM went out. Strangely though, it has not thrown a misfire code.
I'm not exactly sure what direction to go next. Is one problem causing the other or are they completely unrelated. I do have a scan tool that will show the 02 sensor voltage and both appear (at least to me) to be working properly. Is it possible that I've carboned the crap out of everything? I did drive it for a bit when the ICM died, trying to limp it home. It didn't make it though. Any thoughts/suggestions? I really don't want to have to go back to the stealership and have them rape me again on labor charges. At least I can drive it now and at worst could just have them diag it. Guarantee they will tell me I need a cat.
I would call or go to the dealer and tell them that the car started misfiring again. They should have at least a 90 day warranty on parts and labor and they should check the coil pack at no charge because the problem is related to the coil pack so they need to check that is not a defected/broken coil pack.
I think is worth the shot from that angle...
I bought some new delco plugs last night and a can of seafoam. I'm going to pull the plugs and see what they look like, replace them and seafoam the car. I'm sure the heads are not in that great of shape right now. I'm going to double check everything they did and make sure it's put back together right. If it's still misfiring after that, back she goes. Plugs needed replaced anyway.
new plugs and seafoamed. Problem still exists. Could a bad rear o2 sensor cause this problem? According to my data reader, it says the car is running rich.
maybe, but I would still take it back just for a second opinion. if they say the coil is good and something else is causing the problem, then ask them "like wha elset?" and to give you an example.
Yup, it's at the dealer. Dropped it off last night.
They think I got a bad ICM. They swapped another one and it was fine but started missing again after a bit. So the put another one in. Apparently they have been getting some bad batches of these things. They have had this problem before on other vehicles. So it's on it's 3rd ICM now and they are going to keep it and keep driving it until I get back in town on wednesday.
I'm having the exact same problem. I just bought a sunfire convertible with the 2.4L a few weeks back. I didn't really notice any problems during the test drive, and the only reading from the inspection was a bad cat I figured was an O2 sensor problem and thought nothing of.
When I noticed how much it misfired at low RPMs and some gas, I took it to a muffler shop. I figured the sensors were right and I had a clogged cat. They drilled a hole in my exhaust right before the cat and it didn't help the problem at all. They told me that it must be the coil pack. The person I bought it from told me that they just replaced the coil pack a few months ago, though.
I'm planning on trying to pull a used coil pack out of a junk yard to see if that makes any difference, since I'm still not convinced that the problem is from the coil pack. I don't want to spend hundreds of dollars on parts I don't even know will fix the problem.
If you ever fix this problem let me know!!! And if I find anything new I'll be sure to post it here.
My problem was the plastic cover that sits over the coil packs and connects to the spark plug boots. The dealer went through 3 of them before they found one that didn't cause a misfire. Apparently they have had this problem before when they get a bad batch of them.
If your getting a p0420 code I bet your cat is shot. Mine is. When the car misfired, it dumped too much fuel through the cat and overheated it.
When I last took my car to the shop they estimated between $700 and $800 to replace the entire coil pack to fix the problem. Considering that I wasn't even sure that the coil pack was the problem, that didn't seem like a very good decision at the time.
So, earlier today I went a junk yard and pulled the entire coil pack assembly off an old Cutlass. It took me about five minutes to replace my old coil pack with the new one, and now my car runs like a dream! Absolutely!!! no more misfiring problem. For $40.30 I now have a car that seems to work fine.
I haven't noticed any other problems with anything, so I'm going to assume that I'm in the clear for now. Just wanted to let you know what worked for me.
