Pontiac Repair: stalling, screw driver, throttle plate

Question
I recently had my 2000 grand prix's transmission rebuilt by a reputable shop and now I am having a problem with stalling when ever the air or heat are turned on? The rpm's drop from8-9 to five and often flucuate? is this related to the transmission or a completely different problem? and what could cause this? No check engine light on? and if you keep the rpm's near 10 with your foot on the gas it won't stall?

Answer
Hi Patti.

It's hard to say what the problem is but my guess is this It' nothing they did??? They more than likely had the battery disconnected and when it was reconnected the car ran the engine computer basically is confused... If this car has a lot of miles on it I would venture to say that the throttle plate is carboned up and dirty or possibly the idle control valve is dirty with carbon. The computer had compensated for this pervious to the battery being disconnected. after the battery was disconnected that compensation that the computer had in it's memory is now gone. The computer should be able to re learn this on it own.. But in some cases if that is bad enough the carbon.. it can't compensate for it... It's just a guess. It could be lots of other things but that is the most likely thing to try. To fix it disconnect the engine battery and get a can of carburetor cleaner or air intake cleaner and you will have to take off the hose for the fresh air going to the engine and there is a honey combed looking screen in the intake you have to CAREFULLY remove it it has a spring clip holding it in. and with an old rag or a tooth brush spray inside the throttle body and brush and wipe the carbon off the throttle body and the throttle plate. also be careful their is a sensor that sticks down in to the throttle body that is a very critical sensor do not get an cleaner on it or touch that.. If you have the correct type of screw driver you can also remove it before you clean the throttle body. it sits on top of the body and has 3 wires on it. after cleaning the body out you can also remove and clean the idle control valve. you need a special screwdriver for that also. it is a small black round valve on the front of the body with 4 wires on it. remove that and clean the very end of the valve the "pintail" after that is all done re connect the battery and start the car and run it until warm. once warm try turning on the air and let it run for a minute or to and then take it out and drive it. hopefully it's just something that easy.... But with out looking at it it's really hard to say.. It could be something more difficult but hopefully just it's a quick fix.
Good luck!