I am now 1,000 miles into my initial clean faze with Auto-Rx. My vehicle is a 1990 Ford F150 w/straight 6- 300 engine with 52,000 miles total on it. Yesterday I noticed a small drop in oil pressure. I can't tell you what the exact pressure is because the cheap oil pressure guage isn't very accurate. All I can say is that I noticed it drop some. I am currently using some P.O.S. Fram filters for the Rx runs and have a couple Motorcraft FL1's on hand when the rinse faze is over. I'm hoping the Fram's cardboard endcaps aren't the cause. What do ya think? Should I be concerned? Should I change out the old Fram to a new one or trash them both and put on the Motorcraft? Or do nothing and not worry about it?