[PCM] P0304 - Cylinder 4 Misfire Detected (SES) (Old) (History) (Immature)

That's the code I'm getting. I was sitting at a light when the SES light came on, so I'm pretty sure it's involving my idle.

My idle is kinda crappy. Sometimes it wants to stall, other times it works fine. It does idle lean though, and I'm working to fix that.

I should have my Idle VE worked out tomorrow.

I've changed my Idle Base Spark a little bit like the LSJ guys do to help with the cams.

Would a lean afr mixture cause the SES light to come on? Or is there something else going on?

I would turn on the Cylinder misfire counts and log them, will give you a better idea of what's going on.

Check your front 02 censor.. make sure its tight.. no joke exact same thing happened to me.. sitting at a stop light.. idling.. ECL (with that code).. would idle really crappy..

I had a buddy either clear the code or i would just disconnect the neg on my battery. But all it was is that front 02 censor was loose.

Pull the #4 wire from the coil and inspect the post and wire end for corrosion. If thats not it try swapping the spark plug to another cylinder and see if the miss moves. If It doesnt , try swapping with a known good wire, maybe swap with #3. If none of these make any changes, remove the coils and swap them on the Ignition module. If the miss moves, change the coil. If It doesnt move change the ignition module.
This info is taking into account that you have good compression and injector pulse on the cylinder, In some odd case that you dont have compression, the Ignition module swap wont help at all. It will fix a no injector pulse though.


01 cav w/01 3400 gam gt 4t45e