I have a '96 W-210, E-300D. I've had several OM606 cars now but this one is really puzzling me! It's a rather low mileage car with only 135k miles and it's been doing great until about a month ago. At "no load" cruise speeds between 45 and 68 mph, it will start pulsing like your stomping the pedal on a base drum keeping a beat!! You can speed up Or slow down and it stops, and yes, it does it with the cruise on and has NO codes thrown!! Fuel filter is fresh and no air intrusion in the fuel system.....Anyone have any ideas where to start on this??

Thanks, Quigly

 

For those that were keeping track of this thread, I mostly resolved the issue. I pulled my intake and replaced EVERY vacuum line under the hood! Some were swollen & cracked, others just weren't very tight and possibly leaked. The pulsing issue was the butterflies in the intake opening and closing erratically. Fixing all the vacuum issues did resolve the Major issue, however, occasionally it will pulse ever so slightly just due to valve operation.

Quigly