I'm at my whits end with my Air Dog lately. A couple weeks ago I was having pressure issues so i changed the fuel filter and they seemed to go away. Last week during the blizzard I re-fueled the truck and the pump dropped out.... wasn't pushing pressure to the IP. I ordered a warranty replacement and installed a few days later and would push 15psi of pressure for the first two minutes of idle and than pressure would slowly drop off and hit 0psi. Tried to move truck in driveway and anything off idle truck would sputter and stall. I thought water separator may have been frozen so i removed, took it inside and let it sit and thaw out. I put it back on this afternoon and filled with a mix of diesel 911 and diesel fuel, pump does the same damn thing. The only thimg i noticed different about pump operation is that it doesn't come up to pressure as quick as usual and you can normally hear return line from pump dumping into the filler neck and i dont hear it anymore. Any input is appreciated

 

Sure sounds like something is plugged somewhere, I had a fuel line swell shut on me once, was having the same issue as your having, I unhooked the lines from both sides of the pump syphoned some fuel from the tank through the pickup made sure that end was good then blew through the rest, found the bad spot between the filter and the vp.