Hi all, I am new to the forum but have been reading as a guest for some time. I have an issue with my 2004 SS Supercharged. It had multiple problems with the engine when I bought it as a project, including running lean and a P0304 code. The lean issue seems to have been fixed by new upper and lower intake manifold gaskets, but the misfire on cylinder #4 is still there. I ahve tried everything I know, and a friend who is a mechanic at a chevy dealership is stumped. We have tried new plugs,wires, coils, MAF sensor, cleaned the EGR, ignition control module and it still has a severe miss under heavy acceleration. Fuel pressure is good, compression is good and the valve isnt burned. Anyone have any ideas?

 

Also forgot to mention the injector on Cylinder 4 has been replaced....

 

Possibly a bad wire or connector to #4 injector. Sounds like you've done everything else.

 

Is this something that a bad crank position sensor might do?

 

You would get code P0335 if that was the problem.

 

I'm totally stumped. I even changed the plugs and wires around again to see if the miss followed and it is still showing a p0304.

 

Have you swapped around the coils? I know you said you had tried new ones, did you keep them? A new on could be bad from the box, were they brand name? I would switch them around for ha ha's. I wonder if you have a bad connector wire with a bad ground. When I was under boost one of my MSD coil packs side walls plastic was thin and the spark would leap over to the engine causing a miss. Perhaps when it is dark have your hood open and rev it up a few times and look for errant spark at coils, wires. Run resistance checks on the #4 injector connector wire too. Compare to others...

Cam with a worn low spot?

 

I have switched coils but not starting it in the dark. Would I be looking for obvious arcing?

 

Figured you had did the coil switching. Definitely something related to the 4 cyl.

Yes while revving it up look about the engine bay for arching in proximity to the coil and 4 cyl wire. and inj wire conn.

 

no luck.....thanks for the suggestion though