Sfischer042

I recently bought this truck used with 160k miles on it. The truck gets terrible gas mileage averaging just over 11 mpg. It idles a bit rough at idle. It does not throw any codes. I have replaced all 8 plugs and coil packs. That did not seem to help much. I have noticed multiple people with this problem, but no real fixes for it. Has anyone found a solution or have any ideas what the problem could be?

boom50cal

replaced your fuel filter?
did a battery relearn?
cats clogged up or is either exhaust manifold leaking?

Sfischer042

Fuel filter has been replaced. It has a new oil filter, new oil (royal purple 5w20). I cleaned the throttle body and maf. I have inspected for vacuum leaks. All hoses look to be in good shape. The battery was disconnected for a couple days when I did the plugs, so I'm sure it has relearned. I have not tested the cats or found an exhaust leak. I will check for clogged cats this weekend.

boom50cal

maybe even check the FPDCM back up by the spare tire. wouldn't hurt. it may have some corroded connections giving funky values.

Sfischer042

Could it be a cam phaser issue? I don't hear any knocking sounds though.