2000 GMC 6.0 Missfire

[jfthomas327]

This started a couple months ago. The truck had developed a slight miss every now now and then. Mostly at idle and under acceleration. The plugs shows lean so I assumed it to be clogged injectors. Ordered some injectors off Ebay and installed them myself. Fired it up and it still has the same exact miss. This is where it gets tricky. Sometimes I can start the truck and it runs flawless untill it gets warm and then it will go back to missing again. Sometimes when I start it the #4 cylinder will be "dead" and not firing at all. I switched the injector, coil, plug and wire from the #4 cylinder to the #2 cylinder and the miss stayed in the #4 cylinder. I'm thinking possibly a valve sticking? Its confusing the heck out of me because it isn't consistent.

[davester]

could be an injector not firing (so, either a mechanical or electrical issue).

[txab]

Did you check for proper fuel pressure?