My 1994 E420 is surging badly. I replaced the fuel filter as a possible solution but that did not help. I need some guidance in what to check/replace next.

Thanks in advance!!!!

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1973 280 - Sold
1980 300SD - Sold
1982 240D - Stolen
1988 300E - Sold
1989 260E - Sold
1989 560SEL
1994 E420 - Sold
1997 E420
2005 CL500