Have a 98 f150 with a 4.2L v6 n I can't understand why I have really bad gas mileage!! I do have 30 inch tires in it but I didn't think it would hurt it that bad!! I can't go 8 miles down the road without using almost a quarter tank of gas! Any suggestions? Could really use some help.
Thanks

 

I also have a 98 f150 with a 4.2 V6. I'm getting about 14-16 mpg average. I have only had this truck for about a month and I haven't gone through the ignition and fuel system etc. yet but I plan to change the plugs, wires, coils, clean MAP sensor and possibly punch out the catalytic converter. All that should help. If you are not exaggerating about 8 miles per 1/4 tank you have a pretty serious issue I think.

 

Check for codes, even if the CEL is not on. Does the engine get up to normal operating temperature? When it is cold the computer allows for a rich condition just as if the choke was not fully open.

 

Check for a fuel leak. Whens the last time you gave it a tune up?

 

The check engine light is on but it was reading an oxygen sensor and I have changed that since and the light still came back on after I reset the computer. The last time it had a tune up was probly about a year ago