To replace that sensor by itself is not massively expensive, however there have been quite a few problems with the 350 engine and there was a 2010 class action lawsuit in the States regarding this engine and its timing gear/balance shafts etc. Apparently the sprockets can wear, in effect lengethening the chain and causing sensor issues to appear, when it is in fact a more mechanical problem.

I would suggest Mercedes Benz are the people to talk to, no disrepect to your independant but for a car like this, I would speak to the dealer. I know they are expensive, but its an expensive car to own! A mate has a C180K sport coupe that had similar issues but accompanied by rough running and needed new timing chain and sprockets to fix.

However, this could be pie in the sky and it is just the sensor, couple of hundred quid.

EDIT, the E class page came up at the bottom of this one, that was very quick, check the whats bad page..

Edited by countryroads on 07/02/2013 at 17:52