this seems to occur after i've driven for a while, let the car sit for a few hours and then try to fire her up again. i would crank for 4-5 seconds but the car won't start. does not happen on a completely cold (overnight) engine.

anyone know what might be causing this? thanks

__________________
Current cars:
2001 MB E55 AMG
2003 Honda S2000
2000 Honda CRV

Gone but not forgotten:
2004 BMW 325i 5sp sport
1999 BMW 540i sport
1997 MB E420
1995 BMW M3 coupe

Is this the M113 engine? If it is I had EXACTLY the same problem with a 97 C240 with the M112 sister engine... they are exactly the same apart from the number of cylinders. It would start fine hot and cold but require prolonged cranking after about six to seven hours of standing.

I went through a whole process of replacing bits and pieces as there were no fault codes thrown up.

Replaced Crank positon sensor and spark plugs. What finally cured all running problems though was a new Mass Airflow sensor!

Good luck

Doug