Occasionally when my 2003 Toyota Avalon Grande is idling it runs rough and stops, like it's got dirty fuel. It was only occurring rarely, but lately it is occurring more frequently. The spark plugs have been replaced, but the problem still occurs. I intend to sell the car, but would like to get it fixed so the buyer is not stuck with this problem.
As well as the spark plugs, you could change then plug leads, check the coils, and clean the throttle body.