Loss of gas mileage

[BarryBiceps]

2007 Versa. 1.8sl CVT transmission44,000 miles Location: Murfreesboro, TNMy fuel pump went out in November of last year and since then my gas mileage has been terrible. At the time I was under warranty so it was replaced with no charge at a nissan dealership. But ever since that day I have the worst mileage. I filled up today and I got 270 miles out of the tank and I usually put in around 11.5 gallons. I got the dealership to look it over again but they couldn't find anything wrong. Could it just be a crappy fuel pump?

[PapaSmurf2k3]

Could be the incorrect fuel pump, overwhelming the fuel pressure regulator, supplying too much fuel, causing it to run rich all the time.