I recently got a bad batch of fuel in our '94 2500 and now the lift pump went from ticking to making a pounding noise thats louder than the engine. I already cleaned the inlet screen to the pump and it was clean but there was fine silt collected in the filter. Did i do permanent damage to the lift pump and how long can it run like this?

 

Who knows! My lift pump was pounding pretty loudly--stupidly I thought it was the engine knocking at first, but then I figured it couldn't be, and so I stopped worrying about it. But it started leaking and so I replaced it at about 220,000 miles and, hey, the pounding went away! Whaddya know!! The lift mechanical lift pumps aren't too expensive--I think I got mine from Cummins for about $65.