Engine stall when AC cycles

[Jeff Tichy]

Yesterday I had took the ST to the body shop to see about a new windshield and I noticed a "surge" when stopped or at idle. I linked the surge to the AC cycling on / off.



We had the infamous elbow replaced about 4 months ago and everything had been running fine (as far as I know).



Any ideas what would cause the AC pump to drag the engine almost to a stall when it cycles? I also noticed the pump was cycling real quick. 2 to 3 seconds on then off.

 

[EddieS'04]

First guess is the IAC not working or dirty. Second guess is the compressor has too much head pressure, luging the motor down.

 

[scott degroot]

If the ac is cycling really quick have the ac looked at first. When it cycles really quick like that teh iac can't respond fast enough and then you get idle issues. Another thing that comes to mind is that if the truck almost stalls when the ac kicks on it could be that the compressor is starting to lock up adn putting excessive drag on the motor.

 

[Jeremiah Morgan]

My guess is compressor might be locking up!!