'92 Seville stalls at idle -

'92 Cad Seville with a 4.9EFI engine. After driving @ low speeds it stalls when coming to a stop. It starts right back up & then runs fine. Had a complete tune-up, by a trusted mechanic, it even happened to him but he could not identify the problem -no codes-. Happens infrequently but it happens, runs fine inbetween. This car isn't driven much, sits for a week at a time, I've put a gas dryer in it but have only driven it once since then so I don't know if that's a fix or not?? Has this happened to anyone else? Any ideas? Thanks

Lazy idle speed control, bad or misadjusted tps, sticking egr valve, are some possibilities.

Lazy idle speed control, bad or misadjusted tps, sticking egr valve, are some possibilities.