the truck runs great in open loop but hit closed(i.e. warmed up) the thing runs pretty crappy at idle and miss' a bit throughout the RPM range. also under high load it pings, pretty bad too. it also has, not a hard start, but more of a hesitation to start when warm. it gets quite annoying after filling up on gas. my brother says this engine should have more power then it does too, even with the automatic cam it has in it...

i brought it into school a couple months ago, they put an ignition scope on it, and they said the dwell timing(when the coil is grounded again) throughout the cylinders was varing between 10 degrees of each other. i didn't quite look at the scope as the teacher who was a GM tech said its probably a worn distributer shaft, pick up, or ignition module. well, i just put a used distributer in it, with no play in the shaft except up and down like all the other GM disributers i've looked at, and a GM ignition module. the base timings at 8 degrees as this is what my brother ran on his thirdgens.

i've put a differant computer, MAF, TPS, ECT, and various other sensors/relays in it. what else could this be? fuel pressures fine, it does drop imidiatly after shut off which i'm going to cheak the CSI for leakage soon but what else? no vaccum leaks or anything.

 

anyone?