i can only seem to get 15-16 mpg with my x.. what should i do to improve it?
Here are some tips... they depend on your budget.
Stock / a hundred bucks at the auto-parts store and a weekend:
Remove the cross bars on your roof rack (helps with highway mpg)
Engine Tune-up: NGK plugs with proper temp rating/wires/fuel filter/etc
Replace the MAF and O2 sensors
Remove the spare tire and unused seats (helps with city mpg)
Shop tune-up:
Have brake rotors/drums checked for run-out or change the brakes and
adjust out the run-out (if they rub on the pads you lose mpg)
Have the fuel injectors cleaned by a shop (it is a special machine, the bottles of cleanser are useless)
Non-stock / a few hundred bucks and a few weekends:
Change to an electric fan
Install synthetic ATF and synthetic power steering fluid
Install under-drive pulleys on accessories
Install a cold air / larger bore intake system
Install exhaust headers, cat-back highflow exhaust
Change the differential gear ratio and axle bearings
Have fun!
-Graham
1998 Explorer V6 / 310k miles