I have a W210 C270CDi that occationally go into limp. It may run OK for a few days or go into limp after only 5 Km. Cats have been removed. Only errors on diagnostic is EGR valve (cannot remember the code). EGR has been tested, OK, vacuum pipe was disconnected but it made no difference. Injectors have been tested and are OK. Inlet manifold is clean and swirl flaps are working freely. Any ideas? Could this be the (faulty) MAF sensor causing the ECU to "think" that the EGR valve is open when it isnt (read of cases where faulty MAF caused other problems without showing on diagnostics)? Would gladly replace if it is faulty but, since they are expensive I dont want to waste money by replacing a perfectly good one.