does the fuel pressure sensor on the fuel rail also monitor the tank pressure? the fuel pressure reading that i am getting is bouncing between 38 to 39 psi at idle.

 

Nope.

 

so where is this fuel tank pressure sensor?

 

That would be controlled by EVAP canister system and the tank fill cap

Just for the venting the gas while it evaporates.....per say there is no pressure in the fuel tank



It's there to indicate over pressurizing the tank whenever the cap or evap system fail

 

On top of the fuel tank.

 

thanks..