2000 ford mustang is getting terrible gas mileage after the fuel pump was changed why?

i was getting about 325 miles to a tank of gas. the fuel pump was changed and now i am getting about 210 miles to a tank. any ideas why? the fuel system has been pressure tested and there are no leaks.
2000 ford mustang is getting terrible gas mileage after the fuel pump was changed why?
One idea may be that before the fuel pump was not pumping to pressure and thus your engine was running lean. The second may be that the fuel pressure regulator is disconnected under the hood and your running rich but I think you would have burned up your cat converters by now. Does the car stink like rotten eggs? That would be a sign of high fuel pressure. If all else checks out pay for an hour of diagnosis time, let the mechanic determine if anythings wrong. 210 miles to the tank definitely does not sound right.
2000 ford mustang is getting terrible gas mileage after the fuel pump was changed why?
My car did the same thing. Its because your old fuel pump wasn't giving your car enough and now it is. Therefore it makes your gas go faster to you when it is actually right.
210??

wow..

thats tooo significant.

you may be running too rich, check your plugs and if they are really black, somethings wrong.

maybe the EFI, since its fuel injected