why would a new FPR buzz while the car is running? It is grounded, but I dont here nothing when key on? just while running? is it the fuel flowwing through it making noise?? because my other one was old , but never buzzed??

 

Very likely, but Did you go with the aftermarket part?
Do some research about the FPR on the internet. Some people installed those, so they know.

 

i think its the fuel returning to the pump making the hissing noise....