There must be some PCM codes and a blinking CEL light, Idle air valve (IAC) or several other possibilities like the throttle position sensor (TPI). Go to the parts store and get the codes out, it's impossible to tell with no info.
The AC issue has nothing to do with the engine problem unless the compressor is locked up and the engine drags only when it's on, surely a separate issue. It is possible that the engine RPM's are telling the computer to cut out the AC compressor clutch under "assumed" load conditions with a defaulted sensor run scenario condition. ECM/PCM modules automatically cut all unnecessary power in limp mode.
The first thing I would check is the PCM regulated 5 volt line on the TPS to see if you have a shorted out sensor somewhere. I hope that saves you a few bucks on the mechanics that know nothing about electrical. When that 5 volt data power gets pulled down, the engine blows a cog.
Check for vacuum leaks on intake side of engine. Idle air valve, vacuum hoses, Heater / AC control hoses, gaskets are places to look. The fuel management computer is seeing a lean condition at exhaust (O2 sensor) so it adds fuel which makes engine run faster.
your throttle body could be dirty have someone spray in the throttle body with some carb cleaner and hope it works if not it could be a very expensive fix.
I have a 2002 alero that accelerates on its own. When I let off the gas it will stay at speed and continue to accelerate. Alsi when the car is in park it will idle at 2 rpm. What causes this to happen. I just got a new starter put in. Now it seems everything is going wrong. My a/c no longer blows cold air since New starter was put in. Any help will be appreciated. .
