Anyone here own an 4.6 with 3.55 gears? Wondering what kind of mileage to expect when I have the gears changed out from the 3.08's that are in there.

 

I've got "99 with 3.55 and a 5 speed and on a long trip 400mi or more I've gotten 19-20 mpg. Driving to work 40mi one way I can get consistant 18.6 with every tank!!!! Winter maybe 12-14. Hope this helps. Jeff

 

I have the 4.6 but not sure what gears, how would you find out? I seem to get better mileage staying at 55 or less than if
i go over 55. It also seems like it is running to many RPM's at 70mph (I swear I shifted it thru all of the gears )

Mark

 

I'd imagine 15-20mpg, dpending on how heavy of a foot you have when accelerating. My mothers E150 gets around 15-18mpg(~15 when I drive it, ~18 when she drives it.. ) with the same motor and gears.

 

Light foot, 65 mph.

 

I've got a 5.4 w/4:56's and get 12-14 50 city / 50 highway and up to 18-19 all highway at 70 mph. Just to give you the other extreme

Good Luck!

 

I have a 99' 4.6 with 3.55 gears. I have over 130,000 miles on it. It has an intercooled roots supercharger kit with larger fuel injectors, larger fuel pump and a transmission shift kit. With "regular" driving, I get 390 to 400 miles before the low fuel light comes on. I have the 25 gallon tank. I use 91 octane. If I smoke the tires a lot at intersections, I get 300-350 miles before the low fuel light comes on.


My photo gallery https://www.f150online.com/galleries....cfm?gnum=5792

 

You don't say what mods you have what you intend to do tire size or wher you live level or hilly terrain. My truck is heavely modified and running stock 3.55 gears fuel milage is excelant normal driving at 70mph easy 16/17 mpg local short trips 14/15. But I would like to change to 4.11 or 4.33 Before you do an expensive swap make shure what direction you want. I have read in many post where 4.11 gears are no worse on fuel economy.

 

I bought my truck new back in November of 99 and for the past 5 and half years I averaged 14 city and 18 highway every once and a while i will get 19 highway

 

My '97 F-150 4X2 with 4.6L and 3.55 gears (limited slip) has averaged 16 MPG city and 22 MPG highway over the last year using 89 octane. The engine is stock with no mods. Doesn't matter if the highway miles are at 55 or 80 MPH, still get the same gas mileage. Winter mileage drops about 2 MPG.

Keeping the RPM's below 2K when accelerating will gain you another 1-2 MPG. Tires also make a difference in my experience. The fair weather highway tires such as the OEM Goodyear Wrangler AP's gave 1 MPG more than a more aggressive all season tire such as the Yokohama Geolanders.

 

i get 17-18 city and 20-21 highway... 18.6 on highway if the AC is on and im hauling a load

 

I live in South Mississippi, so it is relatively flat, my goal is to increase the towing capacity in my truck in order to pull a small camper that I have purchased with a little more ease of mind. My camper fully loaded weighs approximately 4000 lbs. I plan to leave everything except the transmission cooler stock. Right now I have 3.08 gears which for my particular combination is only rated at 2000 lbs. Right now I average about 17-18 mpg driving in and out of traffic to work about 25 miles one way. If I change the rear end gearing the truck will be rated for 6,900 lbs. quite a bit of difference. I was just curious what everyone else is getting with the 3.55 gears and the 4.6 engine combination. Thank you everyone for your input.

 

Mine is 4.6 with 3.55 and a 5 speed manual, it is a '97. Just got the truck but the first couple of tanks I am getting anywhere from 14-18 mpg.

Mark

 

I have a 2001 SC short box 4x4 with 127,000 miles with no mods, just newer plugs and the usual general maintenance. I get about 300 - 350 miles before the low fuel light comes on. (I dont think it would hurt me to change the O2 sensors. )

 

My 01 Screw with 4.6 and 3:55 gears gets 14mpg or so in the city, 17+ on the highway. To be honest though, I drive like an @$$.