Two things:

1. I've recently added fuel injector cleaner (Valvoline) to a very good running car and it caused skipping and a little shuddering. I think I dislodged some crap on the bottom of the tank.

2. My '94 M104 is very fussy about gas brands - it hates Texaco, Exxon and Citgo but loves Sunoco and Mobil. Shell is not its favorite but it works OK.

Maybe some gas line antifreeze or something for water in the lines and tank would help?

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dtf
1994 E320 Wagon (Died @ 308,669 miles)
1995 E300 Diesel (228,000)
1999 E300 Turbodiesel ( died @ 255,000)
2006 Toyota Tundra SR5 AC 4X4 (115,000 miles) rusted frame - sold to chop shop
2011 Audi A4 Avant (165,000 miles) Seized engine - donated to Salvation Army
BMW 330 xi 6 speed manual (175,034 miles)
2014 E350 4Matic Wagon 128,000 miles
2018 Dodge Ram 21,000 miles