I have a pressure gauge in my fuel line under my hood and it saying 9 pounds.... whats causing this?

 

Pinch off the fuel return line and see if the pressure increases, if it does the regulator is bad. If not then the fuel pump is probably not outputing what it should. I assume that the car does not run.

 

the car runs but seem like its not getting enough fuel.... If you look in my other post in this section named RPMs Jumping there are 3 videos that shows what my car is doing... what line is the return?

 

you would have to check the gas pressure regulator. See if it is broken or not

 

OK, fuel comes out of the pump in the tank, thru a metal line to the engine compartment, into the fuel filter, then out of the fuel filter to the fuel rail. At this point there is a little round widget, the pulsation dampener. You can pretty much ignore it, I just mention that in case you're wondering what that thing is. The pressurized fuel flows past the injectors; when an injector opens some of it goes into the intake. Then at the other end of the fuel rail is the fuel pressure regulator. See the pump runs all the time, moving more fuel than the engine will need. So when the pressure is proper (30-40 psi), the regulator opens and bleeds the excess out thru the fuel return hose. This hose connects to a metal line that goes back to the gas tank. There is also a little vacuum line on the pressure regulator. This controls the exact pressure. Usually it is connected to the intake manifold but on some models it goes thru a solenoid valve first.

If you have 9 psi measured at the fuel rail, I seriously doubt the engine would run at all. It needs to be like 30 or 40.