2002 Chevy Trailblazer A/C STALLING ENGINE

clean the throttle body,here is some info,Engine may stall with the air-conditioner on and or while adding additional loads to the engine at idle. An example of an addition load would be turning the steering wheel left or right with the air-conditioning on. This type of stall usually occurs during idle or slow parking lot maneuvers. This concern may not set any diagnostic trouble codes.

Recommendation/Instructions:
Clean the throttle body bore and the throttle valve plate using a clean shop towel with GM top engine cleaner, GM P/N 1052626 (Canadian P/N 993026) or AC-Delco Carburetor Tune-Up Conditioner, P/N X66-P, or an equivalent product.
post back with any other questions.

I've been fighting the same problem for the last year plus. In time you will likely get a trouble code setting off the check engine/service engine soon light. The trouble code will be for the cam shaft position sensor and the crankshaft position sensor. I was Unfortunate enough to bring it to the wrong dealer for the first 3 tries to fix the problem and got ripped off. With research on line and talking with several mechanics I was told and found out one sensor will set off the other and both will need to be replaced. They are not too expensive, 80 U.S. dollars for the two parts. After the sensors are changed the PCM will need to "relearn" the timing of the engine. This almost has to be done at a GM dealer, and cost about 80 U.S. dollars. Total time to replace both sensors should be 1/2 hour. The cam shaft sensor is very easy to change, the crank shaft sensor is a bear to get at. I choose to change the cam sensor myself, but couldn't reach the crank sensor. Change both sensors and have GOOD DEALER relearn the computer system. Mine seems to be working for now, best of luck.

My 2004 was doing the same thing.Clean the throttle body.Simple and costs about 2 bucks.