Question Asked: Is it the Fuel Pump, CrankShaft Position Sensor, MAP Sensor OR All Three?
January 30, 2013, 03:00 PM
Ran the car ~2-3 months with check engine light on during that time also had tested which read for MAP sensor. Car lost acceleration at highway speeds during normal driving 70 mile daily roundtrip. Let the car "rest" from the first deceleration, restarted fine and accelerated to highway speed again, then another deceleration and no restart. Took to Mercedes tested for CrankShaft Position Sensor. Second opinion found MAP vaccuum hose missing. Replaced hose car ran normally ~1 week, no check engine light, stalls or other problems. Now car will turn over but not start or only "catch start". The check engine light no longer appears and the mechanic shows neither MAP sensor nor CrankShaft Position Sensor error codes. Mechanic advised fuel pump sending unit that can only be obtained directly from Mercedes needs replacement. I am not too sure about this, not only because of the cost but because of the nature of how the problem began.