Attention: TDR Forum Junkies 
I installed my Fuel pressure gauge Sunday and had marginal readings, 9 psi at idle, 5 psi at 75 mph and 1 psi at WOT. I was going to get a new lift pump when I had time. This morning going to work the gauge would drop to zero under throttle and at idle it was still 9psi. At first I thought Installer error was causing this 
. I found no loose connections. Went to local Cummins dealer at lunch bought new lift pump (P/N 3990105) with a date of 12-11-01. Put new pump on. Now reading 16 PSI at idle 12 PSI at 80 and 7 PSI at WOT. 
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I know it has been stated before but here it goes again, everyone should have a Fuel Pressure Gauge if nothing else, even on a bone stock truck. Like stated before in these posts, the truck ran no different at 0 psi, I can only assume I had 9psi at idle due to the injector pump pulling fuel to it. Just my input on how important that one little gauge is, I would have never known without it. Made a beliver out of me.
Brett
. I found no loose connections. Went to local Cummins dealer at lunch bought new lift pump (P/N 3990105) with a date of 12-11-01. Put new pump on. Now reading 16 PSI at idle 12 PSI at 80 and 7 PSI at WOT. . I know it has been stated before but here it goes again, everyone should have a Fuel Pressure Gauge if nothing else, even on a bone stock truck. Like stated before in these posts, the truck ran no different at 0 psi, I can only assume I had 9psi at idle due to the injector pump pulling fuel to it. Just my input on how important that one little gauge is, I would have never known without it. Made a beliver out of me.
Brett
