Originally Posted by REDEAGLE

I got a sierra with a 5.3. Has several aftermarket parts. Got into it yesterday. Afterwards I noticed my truck was missing. I haven't had a whole lot of time to check many things yet just trying to get a good starting point. It misses at idle. If I'm running around 2k rpms you can hear it kinda sputtering like witchever cylinder is missing is somewhat trying to fire. At WOT it "feels" as if it is running on all 8. Any help would be appreciated. It's not smoking or making any funny noises. Does this sound like maybe a fouled plug? I'm getting fire through all coils and wires. Thanks guys