I would doubt a jumped timing situation because it runs so well at other speeds. This engine has a very unique idle air system that uses rubber hoses to inject air around the injection nozzles while at idle to help atomize the fuel. I would be a leak there or a blockage.


------------------
Benzmac:
Donnie Drummonds
1991 GMC Syclone
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM