Ok here we go my car has a stumble or hesitation when you mash the gas, but if you ease down on the throttle the car is fine also when its in park it will rev past 5k with no problems. I've changed the plugs twice, new plug wires, new coil, and a new ignition module. Would a bad TPS cause this or am I looking at a bad OPTI.

 

May be a bad fuel filter, but looking at your mods, you need a lt4 km

 

I've changed the fuel filter also.

 

What happens to the fuel pressure when you have the problem?

 

i had the same prob. on my car and i put it on a sun machine and only under aload it would drop cylinders. so we pulled the plugs and they were black as the ace of spades. the fuel pressure was up at like 58 or 60lbs so we turned that down to stock and i put new plugs in (ACDelco 44lts) and gapped them at .035 instead on the platinums that were gapped at .050 and theat took care of my prob.