Lost economy/fuel pump

I have a 2000 Isuzu Rodeo that has begun to get very poor fuel economy. I used to get 270 miles out of a tank and now I get <200. I also notice the sound of the fuel pump doubles and my gas gauge can fluctuate 1/4 tank at a time. The check engine light also comes on for fuel system pressure drops. I do not smell or see any gas leaking anywhere. Just an extreme loss in economy. ??Any help. Where is the fuel regulator for this car?

The fuel pressure regulator is on the right hand side fuel rail, to the rear. Check the EVAP label under the hood for a basic schematic. Fluctuating fuel gauge readings is due to worn contacts on the fuel sending unit in the tank. Check Amigo-2K's FAQ's for details.
G/luck
Joel