Truck Runs Better With Fuel Thing Unplugged?

[Starbuck75]

 

Hey guys my truck seems to want to run smoother at an Idle and in general with this unplugged? I'm assuming something is wrong because vacuum lines should be attached lol

[HOrnbrod]

Borrow or buy a fuel pressure gauge, hook it up on the fuel rail Schraeder valve port, start engine and check to see if your regulator is even functioning. You should have 31 PSI with the vacuum plugged in, 39 PSI w/o.