Be been gettin 10 mpg here lately and my truck just seems sluggish. I just put some new times on it and I understand they are little heavier than my stock rims and tires and i dont expect to get awesome mpg but they can't possibly be hurting it that bad.

 

Have you cleaned air filter?....maybe fuel filters clogged.

 

Air filter is brand new and it could possibly use a fuel filter but the engine also feels sluggish like it doesn't have enough power. How often is a fuel filter suppose to be changed?

 

30k.

Plugs are 100k but your better off @ 40-60k.

Mileage for your rig?

 

I have 123xxx on it now and I doubt the ifs were changed on it before I got it about 23k ago. The fuel filter has about 10k on it. Could the plugs hurt it that bad?

 

Clean your throttle body.

 

https://www.f150forum.com/f2/ultimat...133049/index3/

Start here

 

I Gaped the plugs to 0.045, they were grater the 0.050 (manual gives a range of .41-.47) and cleaned everything.

 

My mpg dropped by 2 when I put my new AT tires on. What was your mileage before the new tires went on?

 

Don't forget this is an 8 year old thread bumped by random spark plug pictures. If you aren't replying to the post made today, you're question are probably falling on deaf ears.