Concerning the "erratic running" post below, would a bad EGR valve cause this problem? This didn't occur until I disconnected the EGR for vacuum reasons. The Haynes manual says this surging is caused by a faulty fuel pump: how can I check this? could it just be bad fuel filters (or something equally simply and inexpensive)? I don't want to jump to conclusions and start replacing components needlessly. Thanks

What kind of car. Why don't you register and put your car in your signature.

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Benzmac:
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
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'83 300D

Start with the filers. Then when you have off the pre-filter, take off the fuel fill cap and blow air into the line that goes into the pre-filter. It will blow out any excess dirt or algae on the screen in the tank. The other thing that can cause this is the tank check valve. It is under the car and is grey in color.

We sell all of these parts on the partshop.

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Benzmac:
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM