My 1991 Camaro z-28 will not run right when i am going down the road. It seems that when my rpms get high enough the engine starts losing power and the rpms slowly drop until i let of the gas. Then I have to put it in neutral and let the rpms go down until it is idling. Then I shift into drive and it acts normal until I get into high rpms. The longer it keeps running the faster it acts up. I have changed the fuel pump, fuel filter, fuel pressure regulator, oil pressure regulator, oil, oil filter, MAP sensor, positioning sensor, Eg air valve, rotar button, distributor cap, spark plugs(wires),pickup coil, the sensor under the distributor cap, oxygen sensor, and the computer, and it still has not worked yet. Is there anything I could possibly do.

 

catalytic converter.... same symptoms i had on my old 89 iroc, put a "test pipe" in its place, and it felt like a brand new car, and sounded better too. i recomend replacing the cat with a high flow cat. you can get under your car and hit the cat with your palm hard, and if its rattling, 100% replace it. but if it doesn't rattle, it could still be bad.

 

thanks for the tip. I will try it out

 

it still didn't work. I cut the cats out and put in straight pipe. I put it on a computer and it says that my exhaust is rich. also it reads that the temp is -34 degrees.

 

Replace the coolant temp sensor. What about any codes? By high RPM what number do you mean? Have you taken a look at your spark plugs?

 

would it have anything to do with my computer? It happens around 2grand or so