I have a 97 Ford Ranger, 2.9L, 5SPD, the AC works fine at high RPMs or while driving; while at an idle it almost kills the engine when the AC cycles on. When the AC engages while at an idle it blows hot air. I looked under the hood and the engine almost dies when the compressor engages and runs fine and cools fine in between the compressor engaging. Any help with this will be greatly appreciated. Thanks

 

Idle speed should jump a little when the A/C enguages. Maybe what ever does that is not operational.

 

Is their a sensore or something that controles this?

 

The IAC (idle air control valve) controls idle speed. Ford didn't make a 2.9 in 1997, did you make a mistake typing?

 

Yes I did its a 2.3L

 

I'm not real familar with the 4 bangers but I bet the IAC is on/near the throttle body.