96 5.7 Vortec P0102 Troubleshooting

[Bighorns53]

Reviving this for an end to this thread if anybody finds themselves in my position.

It ended up being my distributor was off time throwing random misfires, no cam/crank correlation codes.

Very weird considering unplugging the MAF made the random misfire basically disappear. Not sure how that worked out.

Can anybody answer this mystery? How would unplugging the MAF sensor fix or cover up a timing issue? I purchased another gmt400 (K2500 suburban 8600gvw, thing is an absolute hog NV4500 swapped). Really interested in some of the operations of these older computerized setups. Dealing with a high idle, and of course unplugging the MAF thing runs just fine…

 

[Schurkey]

Unplug the MAF, and the computer reverts to speed/density tuning.

Connect a scan tool, find out what the computer wants you to know.