CHECK for missing grounds. mine did that when i was missing one on the engine. there is one that attaches to the intake plenum where both halves bolt together. one at the back of the engine, goes from the plate on the back of the head to the firewall. one beefy one from the bottom of the block to the batt. I'm pretty sure thats it. somone will chime in if i missed one.
also try adjusting your tps.
http://4crawler.com/4x4/CheapTricks/TPS/index.shtml
