Car stalls at stop lights once / week or so

My 2002 Cadillac (135,000 miles) stalls about once per week at stoplight or stopsigns. There is no stumbling or stuttering, it just quits.It has been doing this for about 2 months. But here is the catch… It ONLY does it when the engine is warm (running for 2-5 minutes). It never stalls after 5 minutes and never stalls when the engine is cold.

When it does stall, it take about 30 sec to a min to restart and it seems to help if I press on the gas a little bit when starting. I suspect… Idle control valve, egr valve. I was wondering about vacuum leaks but I doubt it since it is only stalling at stop lights. Also, once it has stalled, it won’t stall again until a few days later. Never stalled twice on a row.

No matter what things I look at I think it has something to do with the units on the throttle body, or a temperature sensor that is flakey. Oh… .one other thing… when the engine is warm, it seems to idle slightly rough (not bad at all, but seems to barely notice a slight stumbling) I know it isn’t sparkplugs because I has new ones put in. Many Thanks !

Added… Oh one more thing… there are no error codes. No “service engine soon” light.