When I read through the thread, especially post 13, it seems to specifically address the need to change the fuel filters after the first tank. I’m not sure what the second part of your response means, but posts in the thread I linked to suggest that Propel can loosen “junk” in the fuel system. I suppose hypothetically that could lead to some sludge in the tank and possibly lead to a clogged tank strainer. Seems to me like the most cost effective thing to try is to change both under hood fuel filters and see if that takes care of the problem. That seems to be what is suggested in the other thread. Good luck.

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Christopher
'06 Mercedes E350 station wagon (silver/black)
'85 Mercedes 300D (black pearl/palomino)
'85 Mercedes 300SD (smoke silver/burgundy)
'79 Cadillac Sedan DeVille

'05 Toyota Camry (because always running is nice)

'85 Mercedes 300D sold back to orig. owner 8-1-06
'84 Volvo 264GL Diesel, owned 2000-2013