I have a 1986 camaro. The engine idles rough with varying rpms. When in park, pushing the gas pedal causes the rpms to increase very quickly but with throttle wide open the engine idles and there is a loud pop near the intake and MAF sensor. What could cause this? I just replaced the TPS and it is still happening.

 

This is a little confusing. You are saying if you open the throttle plate by hand the engine does one thing but if you press the gas it does something else? That makes no sense on your car because all the gas pedal does is open the throttle plate.

If you are saying when ever the throttle plate is wide open the motor just back fire (regardless of how it gets open) and the car has a general lack of power that can be a few things. You either have a timing issue (spark or valve) or you have limited flow of something. That could be limited air flow, limited fuel flow (filter or pump) or limited exhaust flow (plugged Cat).

 

Sorry for the confusion. With the throttle open to about 1/4 it revs up but past that point and it falls on its face. the fuel filter seems fine, checked the spark plugs and wires. The fuel pressure is 40-45psi is that too low? How do I check for a plugged cat, will it get cherry red?