I've noticed that my lift pump doesn't hum when the key is in run position, I don't have a pressure gauge yet, and don't seem to have a low power problem, however every now and then I have a launch hesitation, is it bad or am I nuts? Also is it worth fighting with the dealer for warranty, I can purchase a new Cummins pump for $106. 00. 89,000 on the truck. What do you think? Thanks