My truck has been down for a while now. Truck is a 2001 2500 HO 6-speed. Cranks but no start. Not getting fuel past the injector pump. Had a code for the lift pump but, fuel pressure is good at 17 or so psi and lift pump runs as it should. It's the frame mounted walbro pump. I'd have done the pump by now except, with my snap on scanner plugged in, the data screen shows the injector pump fuel shut off not switching to on. After I crank the motor it will switch to on for a second and then back to off. I have checked electrical connections and grounds. Could it be an ECM problem or am I just over thinking. I hate to change out parts just on a guess. Thanks for any help you can provide, KyleI'd really like to get it going cause driving my Geo Metro all the time sucks!