I have a lifted 97 f150 w/stock 5.4. It is a 4 by 4 and has 87,000. I cant get more than 10 mpg and the power lacks now with a minor miss anyone have any suggestions. I have changed the plugs and put a k/n air filter but didnt help.

 

Might want to post this question in a teck area for your F150. Also add in your post all mods, tire size, etc.

 

PCV valve, could have a leak. Also could be a COP.

 

plugged cat or exaust

 

I would say clean the mass airflow sensor with an appropriate cleaner, that should take care of it. also you didn't list any codes, is the check engine light on?