fuel pressure irradic??

[kell211]

i've never had a car that had a fuel pressure gauge on it before, so i may be an idiot. i know my car should stay at 40psi, but when you rev it, the pressure increased somewhat. and at idle the pressure may go between 38-40. is this a normal variance, or should the car literally stay at a constant 40 pounds?

 

[kell211]

anybody out there have any advice? thanks in advance if you do.

 

[ek9r]

when you rev the engine the pressure will rise a bit due to the vaccuum created