I have a 2000 Acura tl with 87k miles on it. Recently the check engine light has been coming on when I start the car, but turns off when I drive for a bit. It very rarely happens though. I took it to a mechanic who said it was an engine misfire. He replaced the engine coils, but problem till exists. It seams to happen more when the car is left in the hot sun for a long period. Any idea what could be the problem?