I had a 4.6 in a Mustang but never in a truck. The 5.4 is pretty doggy so I would think the 4.6 would be worse. 4.6's sound better, though

 

Does anybody know what kind of gas mileage they get? Sorry about the spelling I always have trouble with that one.

 

the 4.6 and the 5.4 are with in one or two mpg of each othier, I don't have the exact numbers, but axle ratio super cab, super crew reg cab ect are all mileage factors, Best way for you to know what engine to get is to figure out what you want to do with your truck and what body style you want, a 4.6 with a 373 LTD slip should work fine in a Super cab 2wd, or 4x4.

The 04 Reg cab 5.4 3v ( pics posted in my gallery ) I used to own was a 4x4 long box and mileage was pretty good ( 355 LTD slip ) on the highway, but for city driving, not so great, dependabillity left a lot to be desired, If I were to go back to a F-150, l will get a pre 04 2V 260 HP 5.4 or a 4.6.

the 4.2 with a five speed in a reg cab is not a verry nice truck to drive if your over 6FT3

 

My truck is a 5.4 2v crew cab 4x4 with 33" tires and 3.55 gears. I get around 12-13 mpg city and around 15-16 highway.

 

The 4.6 is a very dependable engine. I found this by talking to many people and dealers. If your not towing alot go with the 4.6. If you do alot of heavy towing than take the 5.4. As long as your in a Ford you'll be fine.

 

I just bought a 06 F-150 with the 5.4L, I just emptied my first tank of gas and was suprised by the mileage it got, 340 miles with the A/C full blast and a average speed of 70mph. 18mpg!

 

I am getting 28/29+ MPG in my 2006 Focus and I have crappy cali gas and do 70-90% city driving. I think that beats the 18 you projected

 

Having driven the same truck, literally, with both engines I can say that the 5.4 is a better choice. I am getting better milage with the 5.4 than I used to with the 4.6.
So you know the History of my truck. It started out with a 4.6 and a few years ago I swapped a 5.4 engine. All the modifications that I had done to the 4.6 I transferred to the 5.4.

JMC

 

http://www.fueleconomy.gov/ (Click on find and compare cars)

I have the 4.6 in my 1998. It's not bad at all in a 4,000 pound truck that does not tow. However assuming maintenance issues were they same I would go for the 5.4. Nothing wrong with a little extra power!

 

IMHO always get the biggewst engine offered.
- better resale (typically)
- I always mod the any engine for more power anyways, so I start with the most power and go from there

 

I think that I will get the 5.4. They basically get the same gas mileage and you get more power with the 5.4. I have been looking, but it is hard to find one like I am wanting. I am wanting a XLT regular cab flareside dark metallic red or dark metallic blue.