I have a 90 300 sel with 140,000 klm on it. It isn't driven a great deal but lately it starts up perfect when cold but if I shut it off and restart after 10 minutes it will sputter for a few seconds and I can smell fuel. After it clears up it is fine until the next time. I thought that maybe injector seals are letting fuel down on the cyl after shut down. What else could it be?