It is a common problem on mercerdes for the fuel filer screen in the gas tank to clog up. On diesels ive see it hasnt made the car stall or anything but on gas ones it can cause your car to stop working completely.

Also listen for air bubbles by the fuel pumps. Thats how I isolated the problem.

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1986 300SDL, 211K,Dealership serviced its whole life
1991 190E 2.6(120k)
1983 300D(300k)
1977 300D(211k)