Still breaking in my 2002 SCrew, 5.4, 1000 miles on odometer. Just got 16.33mpg on a highway trip, carrying about 1000lbs of cargo and passengers. Good or bad? Will it improve after break-in? I expected better, but putting it down to break-in.

 

To me, that's EXCELLENT! I got 15.2 mpg on my only highway trip driving DOWNHILL!! (from Atlanta to Valdosta, GA) I average 13.2 in town on my FX4. Want to trade???

 

Thanks Marc, and no, I guess it's a keeper.

 

That's what those 3.73 gears do..... but you're getting there faster, right?

 

Ralphie,
My mileage got better after break in, but only by about 1 mpg. I have a 2001 Supercrew with 5.4L, 16 inch wheels, and the limited slip rear end (3.55 I think). I just passed 22,500 miles and my trucks lifetime average is 15.8 mpg. On long highway trips it usually goes to 18.8 or 18.9. My best ever single tank average is 19.4 mpg. I am very easy on the foot, especially in town, and on those highway trips I usually only run about 68-72 mph.

Sometime back everyone was talking about mileage and it seemed that the guys without the LS rearend were getting almost 1 mpg better than those who have it. There were one or two guys bragging about getting 21 and 22 on the highway with the 5.4 but I am beginning to wonder if they were smoking something. Did you drive through any mountains? That will wreck you mileage.

 

I have a 2001 supercrew 4X4 offroad. I have tracked every drop of fuel used since day one...strange..i know...but ownersite makes it so easy I have a K&N filter.....SuperChip© and duel electric fans. here are the numbers from 15 months of records, 5-30-01 to 10-05-02.

Estimated fuel consumption for this period is 13.34 MPG The highest was 18.18 MPG, the lowest was 9.83 MPG

The highest numbers were recorded on a road trip from
Boston to Utah and back...the lowest numbers were recorded directly after the Superchip© was installed. The K&N did nothing for fuel mileage. The electric fans have only been in since 8-30-02 and the MPG hasn't changed my average significantly since installation: Estimated fuel consumption for this period is 14.06 MPG The highest was 15.04 MPG, the lowest was 13.24 MPG

 

I haven't noticed any significant difference in gas mileage based on equipment level (not including the 3.73 final drive). (The last time I remember a large posting of fuel economy runs the 3.73 rear was not yet available). It really doesn't seem to matter which engine, drivetrain (4X2 or 4X4), or differential (open or LSD). The biggest common denominator in all of the 20 MPG+ runs was 17 inch wheels. The key seems to be keeping your cruising RPM below 2000. With the 16 inch wheels, 2000 RPM comes up at about 69 MPH, with the 17's, it's about 74 MPH.
I personally drove from Baltimore to Portland, ME (on I-95) and got 20.66 on one leg of the trip (with 16 inch wheels). The secret: I only averaged about 68 MPH. If I let my speed climb above 71 MPH, I only get in the 18-19 range. Around the burbs, I 'm lucky to get over 14. The overdrive ratio one these beasts produces a huge RPM drop compared with the other 3 gears, significantly changing the highway behavior.

 

have about 11k on my 02 4x4 screw. last time I checked mileage I got 12.5 averaging about 85mph for a couple hundred miles and 13.5 averaging about 80mph. Im sure if I dropped it down to 65-70 it would greatly improve.

 

Thanks all for the replies. Guess I'm doing pretty good, considering. I do have the 17" wheels, and generally run under 2,000rpm, and have to drive in the mountains just to get out of my driveway LOL.

 

I have a 2001 Super Crew 4x4 Offroad, with the 5.4, 17 inch GY wrangler r/t's and the 3.55 open rear. I get 15 in town, its got almost 23,000 miles on her clock. I havent tested it much on the highway but it does great in town, as long as I keep it at 1500 RPM or lower taking off from a stop. Using the 4x4 AT ALL will kill the over-all gas mileage, I`ve gotten as low as 9.4 MPG using the 4x4 for almost the whole tank (this was on a trip down to the coast and we drove over 200 miles in the sand).

NO MODS, THIS WAS BEFORE AND AFTER THE K&N, BONE STOCK!

Wes

 

I have a 01 Screw with the 5.4l, 4x2, 36k mi, I have a K&N FIPK, and a straight pipe exhaust (just took out muffler and put in pipe there) I average 17mpg around town + or - 1mpg depending on how I drive and consistently avg 20-21mpg on the Interstate running 75-80mph. I live in FL.

 

I routinely get low 17's on my weekend getaway trips-- about 500 miles over a weekend. Usually just me and the wife, a few small bags, and some trips into town for shopping and dinner. The trip up is usually about 73mph with cruise. '01 4x4, 5.4, 3.55 LSD, 17" wheels, and offroad package.

My "city" driving is mostly expressway to and from work, about 20 miles each way. There I'm very consistantly mid 14's spring and fall, may see low to mid 15's in the summer, but I drop to high 13's in the winter months. We do have that reformulated winter gas, so I expect that accounts for a little as does the drop in ambient temperature.

Best: 17.8 on one of those weekend jaunts.

Greg O.

 

My 02 Screw is a 4.6 2wd. I have kept a log on a spreadsheet since day one (Nov 01) and have done over 30.000 miles.
The uk gallon is about 20% larger than a US gallon. Ours is equal to 4.54 litres. My average gas mileage is steady at 17. Most of my driving is high speed cruising on the freeway, with a little town/city stuff. I assume that this would improve if I cruised at less than 90, but then I would get less work done!

 

I'm only getting between 14 to 15 MPG's with mixed driving.

Should add it's a 2WD 5.4 L.

 

I absolutely agree that keeping it under 2000 RPM in overdrive will give you the best MPG. Just makes sense ! These trucks are big, heavy, and drink a bunch of gas. If we wanted great gas mileage I guess we'd have bought something else. Put your foot in it and have fun.....life's too short not to.