brendalee
Almost all GM products idle rough when its cold but, if it continues it may be the tps swich.
Fast idle motor is not working. This is allowing the idle to fall below the threshold of what it should be when the A/C is on.
Two of the most common causes are throttle position sensor and idle control valve problems.
Temp sending unit for ecm. most likely sensor is bad computer cant read engine temp, fast idle do to cold reading
Over heating (running to hot), Fast idle (Incorrect idle adjustment), Incorrect timing, Carbon build up in combustion chamber,
throttle position sensor believe it or not!
It could have a pin hole in the petrol diaphragm
!t can be the air flow censer it might be messed up or the rong one usually the rong one will make it idle high.
Check the Idle Air control valve. This lets air bypass the throttle body plate when the car is at idle or low revs.
there is no "fast idle solenoid" there has'nt been a fast idle adjustment on passenger cars in over 20 years
Idle compenstorVehicles hve an idle copensator that speeds up the engine when the ac is turned on to ring the rpm back up to the proper idle speed, if yours is too fast then t needs to be adjsted.
Because its broken get another one