Fueling & Injection - Got a problem a big problem

I usually get around 50 to 60 miles to a quarter tank of gas, but recently I am only getting about 25. Does any body have an idea of what this could be?

Need more details I would think. Any mods recently, change in driving habits(in town driving instead of open road), or maybe just needs serviced(new air filter and maybe injector cleaner). Still it shouldn't drop to half the mpg you were getting.

No recent mods, same driving habits, havent used injector cleaner in 2 fills, but I dont think that would cause that much problems.

they change the type of fuel? add more ethanol?

O2 sensors, front pair gone bad.

how many miles on the car?

56000

have you tried changing your 02 sensors?? do you have anyway of logging some data?