all cylinders are firing, but at idle i have a dead miss. my number 6 cylinder was not firing untill i did some upper cylinder cleaner and freed what i imagined a sticky valve or lots of carbon causing it not to close. the truck runs awesome when driving just not at idle. i have done a complete tune up, and checked everything i know to check. the truck had a head gasket installed and sat for two years. i purchased it from a guy i work with i bugged him daily till he finally sold me the truck. other than the miss the miss its flawless. 150k miles and not a spec of rust. any ideas on what the problem could be. im willing to try anything to get the truck back to normal state.

 

Take the ignitor box off the fender and sand under it so that it has a good ground. This worked for a guy I know but I have not seen it work. The ignitor grounds through the case and must have a good ground on the fender (so I have been told).