My Fuel Pressure gauge has been fluctuating for a while between 10 and 2lbs at WOT. Idle always was 13 to 15lbs. (I was thinking the isolator was messing with me) Today it started at 14lbs then dropped to 0 after about 2 seconds. I shut it her down then restarted it did it again, 14lbs then 0. I bypassed the Isolator and restarted the truck. Again 14lbs then 0. Is it the Lift pump or is there a elect problem. You can hear a click like a relay when it drops to 0...

 

Replace the pump it runs right off the computer.

 

I agree. Don't want to be replacing a fuel pump

 

Thanks for the help. I found a pump locally for $200.00. We are leaving on vacation today. I'll be looking into a FASS system when we get back...