It also depends on how heavy the foot is... Also, when it gets colder, gas mileage goes down... 4x4 sucks gas like crazy too

 

Thanks everyone. i took it on a trip and still got that gas mileage on the freeway! i am pretty lightfooted too (hoping to get better mpg). i will check the o2 sensor. i already did the fuel filter some time ago (when i changed out my fuel pump). thanks again.
please let me know if you think anything else is up with it.

 

Don't spend the money on the o2 sensor unless the computer is throwing codes...

 

Let me revise the above statement.

Don't spend money on the o2 sensors unless you check the activity and cross counts on the current sensors.

Lazy o2 sensors could affect your mileage enough to make replacement a viable option even if the PCM isn't throwing codes. But I will never recommend replacement of o2 sensors with out the proper diagnosis (ie looking at the sensor trace and cross counts). STFT & LTFT will also give you an indication of whether it is a o2 sensor problem, a problem with the fuel system, or elsewhere.

 

had poor MPG with my 98. The T-stat was stuck open at 160F and caused to truck to run rich. MPG was about 12.

 

thanks again everyone. i still havent found the problem but havent looked at getting codes read yet.