I have a 2003 Hyundai Sonata that in the past 2 weeks has started stalling after I add gas to the car. I have to rev the engine a few times, and then, when it feels like the car won't stall, I put the car in Drive and release the brake pedal. The car runs fine until the next time I add gas. This started right after I had my oil changed at one of the 30-minute oil change places so I don't know if it is a coincidence that this problem started then or if something was done to my car while the oil was being changed. My mechanic couldn't fin anything wrong, and the dealer never heard of such a problem. I'm trying to save $90, which is the dealer's diagnostic service charge, if I can find someone who may have experienced the same problem and has a solution I can bring with me to the dealer.