looked at 96 sls.good shape.95k miles.car sometimes stalls at stopsigns.what would cause this???

Idle air control valve either dirty or faulty. Clean or replace IACV and also clean the throttle body.

http://www.rockauto.com/catalog/x,carcode,1027819,parttype,6072 --- IACV for your model is not that expensive and fairly easy to replace.

Could be the Traction Control. This thing is a nightmare. I had the switch on mine disconnected because it would come on if I hit a bump or idled at a stop too long. I didn't have the thing completely disconnected just the switch. My '99 is in the shop getting the engine replaced at 158855 miles. These cars are expensive to repair and if you buy one from someone that hasn't taken care of it you probably won't be real happy with it. The SLS (not the STS) is the model that has been copied by several car manufacturers. I have put close to 11 grand in mine. I love this car and for the money I've spent I know I couldn't come close to replacing it. Good luck to you.