Gas mileage troubles

[Triton9]

hey guys,

i have a 1993 explorer xlt thats having fuel problems i believe. when i bought it at the beginning of the summer last year(2011) i was gettin 15-16 in town. now im only getting 12 and 11 at the best. i havent done any engine stuff besides a custom cold air intake and a glass pack on my exhaust. i dont believe that is the problem though. and i only have 100843 miles on it.

 

[Joe Dirt]

CAI could be losing mileage, as well as the change to winter blend gas. I lose 1-3 mpg on winter blend.

 

[92exploder4dr]

Fuel Pressure Regulator (FPR) - is there gas in it's vacuum line on the tree?

O2 Sensor - How old is it?

Cat - Plugged?

Plugs, wires, air filter, properly inflated tires, and finally how you drive.

 

[Triton9]

I know its not the filter, plugs, or wires because i had a full engine tune up when i bought the truck and the plugs and wires were replaced as part of it
As for the O2 sensor and FPR, i have no idea about either...ill look into the O2 sensor and FPR