Thread: Cylinder 3 misfire...please help!!!

Alright, I know I am asking a question for my first post...but I need help!!!

My Car:
99 GTP with CAI, 3" DP,

The problem:
I shut my car off (the car is always warmed up before it is shut off). I then let the car set for about 30 min to maybe 2 hrs. When I start the car up again, it misfires. If I let the car set for longer periods of time (such as overnight or more than 4 hours) the car starts and runs just fine.

When it misfires it throws the following codes:
P0203-Injector 3 control circuit
P0300-Engine misfire detected

So far, I have replaced the cylinder 3 injector and injector pigtail.

Any thoughts? I thought that maybe my pcm has crapped out. Thanks in advance!!!!

Check the plug,wire and coil

Coil was going to be my suggestion also. May be on it's way out. I think I have a couple extra ones around here some where if you need one, just take care of shipping and it's yours.

hey guys thanks so much. The plugs are only a few months old. I will have to try new wires and coil pack. Thanks so much again.

Alright so this morning the car missed right away when I started it up so I headed over to Autozone to have them test my coils and ICM. Sure enough, one of the coils was bad so I went ahead and replaced the coil and put 2 new wires on...I will put the rest on when it gets a little warmer as -14 windchill is not a lot of fun to work in

Anyway, it started and ran fine; however, when I took it out and drove around town for a little while there were 2 periods of time (about a minute probably) where it would misfire again. It was running a lot better than it was before I replace the coil pack and wires. Would this happen because the computer is trying to relearn?

That could be.

Welp...my car is fixed the coil pack fixed it...now i just have to replace one of my idler pulleys, track bar, and blower motor...not sure why all of this stuff just decides to go bad at once

Originally Posted by swifty

Welp...my car is fixed the coil pack fixed it...now i just have to replace one of my idler pulleys, track bar, and blower motor...not sure why all of this stuff just decides to go bad at once

good to hear. your car is over 10years old and a GM product.

Welp...bad news...my car just acted up again after running flawlessly for over two weeks. I came out of the grocery store and the car misfired again when I started it up. I think I am going to have my coils and ICM tested again tomorrow and see if that helps. Any other ideas???