i've been trying to diagnose a few issues for a long time now, that may be related. car is hard to start, and my avg fuel mileage dropped to about 13 (used to get 18+). all 4 plugs on the passenger side will be fouled after a few hundred miles and they'll also be wet when i go to check them. i originally thought it was oil, but i noticed that i have fuel in my plenum, so i think thats excess fuel in the chambers.

i went to do a fuel pressure test at the rail, and the gauge goes up to normal when the pump turns on... but as soon as the pump turns off, the pressure drops down to single digits.

i thought maybe i just didnt have the gauge on all the way, and when i went to check it, i heard a hissing noise. i pulled the gauge off and it continued... while trying to pinpoint it, i pulled the vacuum line that goes from the fuel pressure regulator to the plenum and fuel was gurgling out of the line.

is this a pretty clear indication that the fuel pressure regulator is bad?

 

Absolutely.