@5.9cummins, one of the items I've been doing for years is puting in 2 stroke oil each fuel fill. The pre '07's were designed for higher sulfur fuel then todays ULSD sold. Adding it helps lube the lift pump and injector pump where the older fuel use to do. Might consider that. The '04.5 thru '06's only need 1/2 oz per gallon since they are designed for the LSD, but can use the 1 oz per gallon ratio. It has made my engine a little quietier as an added plus. Not sure if anyone mentioned this to you or not.