For a good diagnosis, it would help to have the following questions answered: 1) Do you hear the frequency valve buzzing? 2) What is the condition of your alternator? I know this sounds unrelated, but if you have a Ducellier or an otherwise weak alternator, it may not put out enough juice at idle to keep the car running well -- especially after sitting at a stop light with the radiator fans pulling the battery down. Watch the volt meter on your dash, and you will find out if this is your problem. Anything under 11 volts is a definite problem. It sounds like you are describing a weak alternator not putting out enough current at low RPM's. Hope this helps, Walt Tampa, FL