hassgrant

I have a 91 Camaro Z28 305 TPI with manual transmission. When the vehicle is first driven for the day or after sitting for awhile, she runs hard with crisp acceleration and take off. After she runs for a short time, usually less than a few minutes and miles, she falls off at acceleration. Her idle is always steady either way; however, sometimes sits around 750 RPM and sometimes sits higher at about 1250 RPMS. I have replaced the ECM, the O2 sensor, EGR valve, points, fuel filter, vacuum hoses, plugs and wires replaced within last year, fuel injectors and fuel pump are about two years old, and I checked the MAP sensor to make sure she was within norms with ignition on, engine off, and with engine on with WOT and moderate throttle. Now, my EGR solenoid is for a 91 Caprice 305 as solenoids are impossible to find for 91 Camaro 305 F engine code. The solenoid is getting power, and I can hear it click open and closed when I send 12 volts to it. I also get vacuum from the solenoid when I rev the engine. So, does anyone know what the problem is? This has been a problem I have been living with for awhile. I am tired of troubleshooting by replacing sensors here and there. Thankfully Advanced Auto Parts is good enough to let me warranty my parts and it doesn't hurt the pocket book as bad. I appreciate all help in this matter.

hassgrant

Correction to post - I replaced the ICM not the ECM, but the ECM is only about three years old.

hassgrant

Ok, this morning, car ran great to the gym, about 12 miles. I thought, perhaps that she had reset herself and would be all better since I did all the testing yesterday after she was warm and never let her cool down. Wrong! She ran like **** again from gym to home. Weird thing about this morning was that she was idling at about 1500 RPMS, thought that was because she was cold. She also should low volts. Just before I got to the gym, my stereo system shut off, then turned back on and volts went to normal. When I left the gym, idle was great, volts were normal, but she ran like ****. What the hell is the problem here? I still think vacuum, but I can't locate the leak. Could my timing have slipped? The O2 sensor is brand new, few days, so I am ruling that out for now. Could it be TPS? When she is not in gear she revs up just fine, with just a slight hesitation when you first stomp it, almost like she is taking a gulp of air. Anyway, I know there are a lot of brilliant minds here, so I hope you can help. I appreciate any advice.