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Message: [QUOTE="EMD_Driver, post: 86847, member: 2185"] After all the fuel pressure problems I've had, I thought a new pump would solve them... All this week, the pressure would immediately come up to 70PSI and hold there, for about 3-5 minutes. It would then drop sharply, depending on how much pressure I had on the go pedal. I figured my new fuel filter might already be clogged, but hadn't changed it yet. I installed a post-pump filter this evening and had to mount it horizontally. That kept me from being able to fill it with fuel, before spinning it on. I decided to try just pushing the air through the system, and back to the tank. I temporarily have my fuel pump wired to a relay, so it gets power directly from the driver's side battery. I bypassed the relay and just let the pump run for a while. Using the OBS fuel pressure regulator allows me to hear the air, when it goes through the regulator.. Kinda cool sounding.. When I first hooked up the pump (With the truck off) It sounded nice and fast. The pressure built up and I eventually heard the air going through the regulator. After about 4 minutes, the pump started slowing down. The pressure also dropped to 65PSI. The longer it was running, the slower it got. It did keep maintaining the 65PSI though. I'm wondering if there is a design flaw with the pump, or if it's supposed to do that. I know it wasn't my W85 fuel, since I filled up with D2 this morning.. The check valve part of the pump is still working, as evidenced by the bath of diesel I got, then I pulled the line from the pump outlet. I'm kind of at a loss on this one.. If the pump were still wired to the factory harness, I might think it was a voltage issue. Since I'm wired directly to the battery, that rules voltage issues out. Anyone have any ideas? [/QUOTE]