Heres the problem. The car seems to idle fine but when you jab teh throttle the car stumbles, no matter the rpm but its more prominent from idle, and if I hit it hard enough it will die.
Heres what I have done. Checked plugs and they are gapped at .035, new MSD wires, swapped out coil, new ICM, newer enigne harness( 40k miles vs 170k), different ecm and tune. I had an opti that only had a few thousand miles on it and did a warranty exchange on it for a brand new one. I have been told by Ion that a few people have gotten bad ones that were brand new. When I put this last one together I put loc-tite on the rotor screws and the opti pigtail is clean. New IAT pigtail and sensor, new map and MAF sensor as well as a new MAF pigtail.

I guess my first two questions would be:
1) COuld weak/worn vlavesprings cause a stumble. I am running beehives good for .600" on a .608/.628 cam.
2) How many people have gotten brand new optis that were bad?

Thanks for any help

 

Is it only when the cars hot or all the time? Mine did that when it got hot.. I dont know exactly what fixed it but I replaced my torn intake elbow ad did the ICM cooling mod and it was gone. I also replaced the EPC solenoid in my transmission at the same time.. dot know if that would help at all but one of the three did something...

 

I got money on its a wire. Lt1's love to munch wires, Double check em by taking them off one by one.