My 90 Iroc is still missing out. It does it at 1500 RPM and at 3000 RPM. These are the two engine speeds it's the worst at and seenm to trigger it. I have a suspicion about my fuel pump but I have put on an adjustable fuel pressure regulator so how can I check out the fuel pump now? It doesn't do it in neutral, only with a load on the engine. The distributor cap and rotor are new from this summer, I've got new MSD wires plug wires to put on. The ones I have aren't too old to begin with, just a couple of years. I've also put on a new O2 sensor. Please help me, I can't find whats wrong with this and it's driving me crazy! Thanks!

To check your fuel pump get a fuel pressure gauge and check your fuel pressure. guys on the board here say the pressure will fall at wot and/or higher rpm's from the idle pressure if the fuel pump is failing and can't keep up. i'm sure someone here has the "proper" technique though. good luck.

I've done some searching now that the search function works, I've found old problems people were having that are identical to my problem. When I say that the car is missing, I'm saying that at those cruise speeds the car starts jerking and bucking. Sometimes if I hammer the gas when that happens it starts to backfire in the catalytic converters (they're gutted). Well anyway, the people with problems like mine turned out to be their fuel pumps which is what I was afraid of. I'll get the gauge on there and see what's going on. Thanks

could also be the maf. haad my chip burned from ed wright annd cursed it cause it made no difference.found out later the maf was going but wouldn't throw a code at all.

Sorry, but my car is Speed Density. I appreciate your input though!

What about your plugs, wires, rotor, coil IGNITION!

I had the same problem and it turned out that my number 8 plug was all fouled up!

Also you might want to check your fuel filter!

I had the same problem..turned out my distributor was not doing well. By the time I figured that out I had replaced every ignition component with msd, so I bought an msd distributor as well.

I just got done dealing with this issue. If nothing is helping, check the injectors. All you need to do is an OHM reading. I belive the readings should be between 11 & 14 ohm's. Any lower and you have a bad injector. We fought for a week with this. After 15 minutes we found the problem was an injector reading 8 ohms. Replaced and ran like a champ.

Hope that helps.