This is the first forum I have ever been on so bear with me. I have a 2007 stx 4 wheel drive completely stock. What kind of fuel mileage difference is there between the 4.6 and 5.4. I am thinking about trading up to the 5.4 if there is not much. I will be installing the 2.5" leveler kit on wichever truck I have. I just got rid of my 96 F150 with a 6" lift and 12.50x36.00 that got 12 miles to the gallon so I dont want to end up right back there.

 

Probably about 1 mpg.

 

Over the years I have found that if you have a 4x4 don't expect good gas milage. This comes from 50 years of driving 4x4's.

 

yeah and if you lift it your truck is pretty much a sail in the wind. no aerodynmics at all. so that wont help your gas either. but lifted trucks are just cooler!

 

Yes it took me a while to reply I'm a truck driver and I dont get on the computer alot. I dont expect good gas mileage but I dont want to completely kill what I am getting now which is about 17 around town.

 

If you are getting 17 around town in a 4x4 4.6, you are doing extremely well. I'd expect a 5.4 to get 14 at best. You either have an exceptional engine or you drive like an old lady - either way, if it ain't broke, don't fix it!