What do your mean?

 

the fule pump runs continuosly when the engine is running. It supplies more fuel thent he engine can use, all the extra fuel returns to the gas tank. This cycle cools the fuel, plus it spreads the contamination through the entire fuel system. Run a can of seafoam through the tank, then replace the fuel filter again.

 

Glad you found the problem. I'm not sure that you would have too much trouble with the return lines as the fuel filter should catch anything before it gets into the rest of the system... Well that is unless the filter gets cut, allowing junk through, but you would also be experiencing problems with the injectors. Seafoam or any injector cleaner for that matter won't hurt a thing. I run Chevron w/ Techron at every oil change.