I have a 92 flairside reg cab with a 4.9L 5spd and 3:55 gears. The fuel mileage has been dropping off from 16-17 mpg to the other day 9.36mpg. Does anyone have a clue where I need to look 1st to get my mpg back up.

 

first place I'd check is tire pressure.

 

Is your check engine light on (and if not, does it work)? What's the maintenance history like (especially recent)?

 

also, a buddy of mine who worked at an auto parts store always said "when in doubt, replace the oxygen sensor"

if you have had the vehicle few years and never replaced it, it's probably pretty fouled and that will decrease your gas mileage. (if the vehicle is new to you, do you know if/when it was last replaced?)