My 230 Kompressor had this start up problem last spring and it doesn't start up smoothly, I switched to mobil synthetic and it has been fine until this summer. It coughes to start up the first time. I don't drive the car everyday and even I do, it seems that it still hesitates to start the first time especially when the weather is warm. Any ideas or places I should have the dealer to look for? It only has 16k miles.

the 111 engine is notorious for fouling spark plugs, especially platinums, this would be a good place to start to look.