So here's what I'm thinking. As you might know, lift pumps on its way out, probably the check valve sticking. My thought is, the new ULSD is the culprit. Yes I know these pumps are marginal to say the least, but the truck only has 23k miles on it, and now with the ULSD being run for the past several months, my conclusion is the ULSD isnt lubing enough for everything to move freely. I run Power Service white and half a quart of 2 stroke in every tank, I think im going to step up the amount of 2 stroke after my walbro gets here and start running the truck again.