Im getting 12.5 MPG. I know alot of it has to do with my original plugs and 178k miles, but any other things on the 5.4 3v that is known for causing fuel mileage problems?

 

My gas milage hass dropper quite bit the lasst several weeks. My ir filter is clean I just changed my fule filter. I seafoamed the intake, and I have runt several bottles of fuel system cleaner through. I'm guessing its the "winter mix" of fuel. You may not get as good milage as you do with the "summer mix".

 

There is far too many variables which could factor into why your getting 12.5 mpg. Around town, that's pretty good. Do you drive with a heavy foot? Lifted? Tires?

My bone stock 5.4 crew cab 4x4 with the 5.4 is currently averaging 11mpg around town. Course it's also been in the low teens the last couple weeks and winter fuel mix is playing into this as well. As always, YMMV.

And change those darn spark plugs.

 

I have larger tires but when I got them at 120k miles i was getting about 14 with them. Im getting 12.5 on the highway with the cruiser haha. I have a K&N, dual exhaust, programmer...

 

I had Sport AT's on my truck when I first got it and was able to manage 16mpg..

I then got some Goodyear Wrangler MT/R's and dropped down to about 14mpg.. Same size tire and all, just a MT vs AT and they weigh alot more.

I got a programmer and back to about 15mpg.

 

I get 9 in town and 14 highway right now... That's with winter fuel and 4.10 gears though, I was getting 17 highway this summer

 

Yeah Im getting like 10 in town and 12.5 on the road. Im running 37" mud grapplers on 20's... Thinking of downsizing to 35"s for better mileage.

 

man, im getting that same mileage with 33s and stock 18s.

 

Does anyone notice a drastic drop when towing? Or is the mpg so bad already it can't go down lol

 

178000 miles on the original plugs???
sounds like you answered your own question....A tune up might help.