Quote Originally Posted by 1project2many View Post
Hey! Stop deleting posts!!! lol... I just got done moving the other thread.

You've changed so many parts that you should be looking at the few that have been re-used. Is it possible that the distributor cap to rotor phasing is off and the wrong cylinder is receiving spark? Or maybe there's a problem with the coil? Is the distributor wiring laying on plug wiring anywhere? Is the pickup coil correct for the module (there are clockwise and CCW parts)? Did you re-use the balancer? Is it possible the outer ring is no longer in the correct position? Or is the balancer designed for a different timing cover and the mark is not lining up at TDC?

You should have tools to monitor what the computer is seeing and commanding. A scantool or a laptop with scan software and a cable will work. Check timing at the balancer against what the ecm is commanding. A simple spark test tool can give good indication if spark is constant and steady. Confirm the throttle body and injectors are correct for the engine displacement. If there's an EGR make sure it is not opening (this usually gives a sag without backfire, but it helps to check everything). It can be really tough to diagnose a vehicle over the 'net but sometimes with enough patience and persistence it can be done.
Sorry for the confusion and thanks for cleaning up my mess! I should have elaborated a little further. This was a new long block and ALL sensors have been replaced with new ones, new injectors, dizzy, plugs, wires, EGR, etc. The only thing not "new" is the TBI assmebly (even though I've cleaned it twice to ensure it's good to go). I'll have to look into where to pick up a scantool or a cable/software to monitor with the laptop.