1996 E300 Diesel Surging. Please Help!

[rthomas63]

I own a Mercedes Diesel E300 with 48,000 miles. 3 months ago the car began surging and lunging between 2000 and 2500 rpm (between the speeds of 55 - 68). If you are going over 68 mph it is fine. It does not do this all of the time but it does it more often than not at all. Took it to the local Mercedes dealership where they replaced vacuum sensor and another part ($500 + ). This did not solve the problem. Does anyone know what the problem is? I would appreciate any help or suggestions.

[Gilly]

The main problem is the dealership took over 500 dollars from you, yet the car isn't fixed.
I'd post this over at the Diesel forum if you haven't already.
With 48,000 miles it's difficult to believe anything is worn out, so I'd suspect maybe a problem with the injection pump itself. Have the filters been replaced lately (they are supposed to be replaced based on time as well as miles).
You could also suspect the drive sprocket for the injection pump, I believe there is some sort of adjuster built in to the sprocket which could be not operating correctly.
Gilly

[rthomas63]

We took the car to a diesel mechanic who specialized in injectors and he was 99% sure that the problem was not the injectors. We changed the fuel filters in November. I've posted the problem on the Diesel Forum as you suggested. Thanks for your help. We are going to check into the adjuster on the injection pump.