Here we go again! '87 IROCZ/28, TPI350, TH350, bone stock. The car begins missing AFTER it reaches operating temperature, and then only at 1/2 throttle or more. At WOT, it's worse. At 1/4 throttle or so, everything is fine. It's good at 80 mph as long as I don't "load" the motor. WASSUPWIDDAT??

 

Still have a cat?

 

Yes. It has A single CAT on the passenger side of the undercarriage.

 

Make sure it's not clogged. Is your car running hot, or at nite see if it glows once the car heats up.

 

How long has it been since you have changed your fuel filter???? Or maybe just a tune up.

 

Fuel pump is 2 months old. Fuel filter is 1 month old. Tune-up was last month, with new MSD cap, rotor, wires, and Bosch plugs. How do I know if the CAT is plugged or not??

 

 

Your cat isn't clogged. If you haven't replaced your stock ignition coil with an msd one, you might as well. If it's been over 60k since your replaced your oxygen sensor, go ahead and do that. I was having similar problems with my car last year and after I replaced the o2 sensor, coil, plugs, filters, wires.. I replaced the entire distributor, cap and all, with an msd unit. I paid $230 and my problems went away.

 

Thanks, guy's. In response to "rezinn", the coil has not been replaced by me, nor has the O2 sensor. Thanks for the advice. NAPA will get a visit from me in the morning. QB

 

dont forget to check those plug wires.........easy fix if they are bad......

 

I bet it's a fried wire. A bad 02 sensor will not make your car run bad at WOT. The ECM ignores it at WOT...

 

Bad TPS is my best educated guess. Try scanning it or if you have a digital VOM try that. Another thing is the coil could be going bad.