Maybe this is going to sound really stupid, but I beleive between us we located the cause. 3 of our trucks started getting louder ( the normal ticking a diesel makes ). Mine was darn near sounding like a Powerstroke. While sitting at a red light, the oil pressure was erratic. I was not far at all from a T/A truckstop, so I stopped there to see if they could help me out, cause I certainly didn't want to blow her up. The Diesel tech took a look and almost instantly he said " There's the culprit, a Damned old Fram filter". " I've seen this too many times" he said. Now having used Fram for years on gas motors, when I changed the oil, I used one. I told him that they meet or exceed mfg specifications, how could that be it ? He said let me show you something. He cut it open and cut open a AC Delco ( Which he had done a Virgin oil change on a new GM truck earlier ) out of the trash can. " See anything missing"? By gosh, he was right, The PH9100 FRAM did not have the bypass valve in it that the AC had. He didn't have a Donaldson ( which he said was his first choice ) filter in stock for it, so he got an AC Delco from the local Chevy dealer, Filled her with Mobil Delvac 1300, and she shut up, got steady great pressure, and beleive it or not, my milage has returned. I notified my friends as they use FRAM PH9100's ( we kick in and by them by the case ), and are getting the same results after changing over. It wasn't the fuel after all.
