I've done a V6 to V8 swap on a 2002 GMC Sierra. I rebuilt the 5.7 and installed a T/C 220/230 cam with 116 degree lobe sep. The truck idles good and shifts fine, throttle response is crisp in Park/Neutral, but acts like a choked chicken when you apply a lot of throttle in drive. If this were a carb'd engine with a distributor, I'd say the dist. rotor arm was broken or the timing was 1 tooth off. When I initially started the motor, I did the crank relearn procedure to clear the P1336 code. I did this again last night (misfire code set) to see if it would help and I made things worse. I can hear what sounds like leaky exhaust but it's coming from the intake manifold, which tells me the intake valve hasn't completely closed before the cylinder fires. This sounds like a timing issue to me. Also when you hold the throttle open and the engine revs you hear popping back through the plenum. Again, timing issue.
Needless to say, I'm at a loss and need some help from some of the more knowledgeable/experienced LS folks.
I posted the tune file on the HP Tuners forum if you would like to look at it.
Would appreciate any suggestions or hints.
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