I have a 97 jeep that i put a 96 4.3 v6 engine and a 4l60e transmission with all the emissions, orginial wiring from the chevy blazer, the fuel lines the fuel pump, sender and gauges, and the instrument panel from the blazer. all hooked up and working. it is throwing no codes. the problem is it has a miss when you just start to push and hold steady on the accelerator, but if you just rev it up no miss. doesnt matter if it is in drive or park acts the same. the odd part is after about 45 minutes of driving it stops missing almost completely. I have changed the spark plugs, the cap, the rotor, the wires, have swapped working coils, pickups, tps, map, maf, egr, iac, off of same year and model working chevys, to no avail. also the motor is a new rebuild all new gaskets and o rings. I hope someone can shed a little light on the problem. thanks.

 

It is possible that there is an issue with the spider not spraying consistently... Have you run a rather stiff regiment of injector cleaner through it?

 

i haven't yet. so it could be possible, but i didn't see anything wet inside the manifold when i took off the tb and looked inside. but i will try that and see if it helps.

 

anyone with any other ideas, or suggestions. need all the help and input i can get. thanks