Hello, I am new to this forum and have found a lot of interesting reads. I'd have to say I don't know much about MB engines. I have a 1994 C280 (auto trans) with about 150k or so on the clock. It has been running really rough. It starts fine but even when it is idling, it coughs or sputters the whole time, the rpms jsut don't stay steady. It just keeps fluctuating. Even while being driven, it still fluctuates like that. I have had this problem for months now. Before, it used to only do this every so often. Now it does it every time. A friend suggested cleaning the fuel injectors with the Chevron cleaner. Should that be the first step I take? What else could I do, or what could the problem(s) be?

Any help would be appreciated.
Thanks.

 

Have you owned the vehicle very long? Maintainance history?
In my book - Ten years & 150,000 miles would warrant a good basic service including compression & cylinder leakage tests. (to establish a baseline).
Too many things can cause the problems you describe. Adding a fuel injector cleaner can't hurt.
I would also look closley at the engine wiring harness for cracking or deteriorating wire insulation. (usually evident at the fuel injectors and temp. sensors). I've replaced quite a few harnesses on these motors. Seems to be prevaliant on the early to mid 90s from my experiences.

 

if you hear the backfire on the intake side during acceleration, then only two things.

sparkplugs and/or air mass sensor. [sm=smiley20.gif]