I have a 2002 Yukon with an ATI Procharger. Recently I've been getting SES lights for a missfire on #7. I know that there have been a lot of problems with guys blowing #7, but I don't think my cylinder is shot. No smoke, no rough idle, no performance change. I pulled the plug and it looks normal, no oil or anything.

I changed the plug, wire, and coil but the light came back. I ATAPed it and found that the engine only misfires at lower RPM's and stops after 1000 rpm.

I'm gonna do a compression check on #7 tomorrow to find out for sure if the cylinder is shot or not. Any other possibilities? Maybe the injector???

 

Interesting. I doubt that its an injector. If it were, you have a big problem and you'd know it.

 

I wonder with the number of problems with the #7 cylinder with the ATI prochargers if there is a fuel distribution problem unique to the combination of the ATI supercharger and truck intake manifold?I think I would be asking some serious questions to ATI's research and development people.The problem seems to widespread for them to be unaware of it.I hope your problem is not major,but I would definently let ATI know about it.