The problem first started about week and half ago and would only occur when engine was warm. When idleling my RPM would hover from 500 to 1000 rpm. When I accelerate there is total lack of power and seems the more gas you put to the engine the more the engine holds back. Then it started occuring all the time and not just when car was warm. I have also noticed it has been hard to start my car after this is occuring for long period of time. Would start when car sat and cooled for a while. I replaced the coil distribuor cap and button wires and plugs. I also just had my fuel pump replaced. Problem still persists. If you have any suggestions I would be very greatful. I was curious has anybody heard of the EGR(Exhaust Gas Recirculation) causing this problem. They say that if the valve is malfunctioning it will cause your car to run rough both at idle and acceleration. Let me know what you think? I have a 89 Firebird GTA with a 5.7 350 TPI engine. There is a very noticeable difference bc you can hear and feel the studdering. It almost sounds like a thumping noice occuring ever second. When at idle speed the fluctuating of the needle is almost a pattern it boggs down and then revs up and then boggs down again. I did check all the vacum lines but i did not find any loose or cracked. My timeing is set at 6 Degrees . Any ideas?

 

does it feel like something is REALLY messed up or is it just sort of holding back from what you are used to ... does the car shudder when you floor it... does it sound bad ??... what does it sound like ??..
what engine/fuel injection does your car have (what year is it) let me know and I'll have a little better idea of how to help you... also ... check all the fuses AND every single vacuum hose going to your engine..
reply with the info on your car, And I'll see what I can do...