Ok,I replaced the fuelfilter this morning,but the problems are still there.I noticed at first after I put the key on the ignition stand for 4 times to fill up the filter with gas,that after I started the car it started smooth and after it warmed up a bit I got at least 5500-600 revs easily,so I took it out for a testdrive and that was that.
4500 rpm,and it cuts out.
So I'm gonna make an appointment at the local Mercedes dealership and they can play with it,see if they find the problem.
BTW,what's that thing besides the fuelfilter with a membrane(right word?) in it,a Bosch part,it has a line straight from the fueltank-then the thing- and then on to the filter,any ideas?