Hello and thanks in advance for all of your help...I have a 1999 STS with 147,000 miles. I've had a mechanic friend already take a look at the vehicle and had him bring his computer home from his shop and hook it up to see if we could find the problem. We changed the fuel filter, cleaned the grounds, cleaned thethrottlebody and the car still stalls constantly when you come to a complete stop or the vehicle reaches a certain rpm (below 1000 rpm). It starts right up and runs great down the road, excellent acceleration, no hesitations or anything,. The only problem is when it gets under 1,000 rpms, the vehicle stalls. Sometimes at a stoplight, the engine pulls out of it on its own, like its going to stall out but it catches itself and continues to idle smoothly. Could this be the air idle control motor (valve) or another problem like a clogged fuel injector? I amcurrentlyrunning some of that B44 injector cleaner and am trying to exhaust all options before taking it the the Caddy dealership here in Omaha. Thanks again for your suggestions and advice...Mike

 

i be adjusting the idle control AND checking the intake throotle valve for buidlup of carbon.

then report ...

 

Your problem sounds familiar.
I had an Olds that would stall like you described.
I would have todropin neutral when stopped to
avoid stalling.

Anyway, it turned out to be the ERG valve.
Hope this helps.

-jasper