i have a '99 f150 with 4.6 and 175k. it used to get around 20 mpg on the highway but recently the best i can get is about 16.5mpg. just wondering if anyone has used run-rite fuel injector cleaner? i watched a video where they hook a canister to the fuel rail. thanks.
brandon

 

the general consensus around here is the only fuel system cleaners that work are Techron and Gumout with regain.

 

alright just wondering...the truck runs fine except for the poor economy, saw the run-rite cleaner on youtube on the scotty kilmer channel, but i guess he has no clue what he's talking about...lol

 

It's more likely your gas mileage issues are due to ethanol and winter blend gas. However, how many miles are on your spark plugs and front O2 sensors?

 

The plugs have about 12k on them. The O2 sensors have 175k on them.

 

I'd change the front O2's. They are past their normal service life, but not impaired enough to trip a CEL.