I feel your pain. I have a 2000 5.4L 4x4 and get about 12 mpg in town w/o trailer and about 8 mpg if I'm lucky pulling my 14x7x7 enclosed trailer fully loaded weighing in at about 6,000 lbs. I was really suprised the first time I pulled the trailer with how little power the truck has, Can't even use the cruise control over 65 because it down shifts on every overpass or hill.

I am seriously looking at the diesel Excursion 4x4, heck it gets better mileage in town & on the highway and will pull the trailer with the cruise at 80 without even sweating.

 

I was having the same problem with 3.55 gears and 305/75/16 tires. The heaviest load I pull is 3000 lbs. I changed my gear ratio to 4.56 and maintain a constant 13 mpg. Even with a heavier load (I helped a friend move, pulled a 16' trailer loaded) I still managed around the same mpg. I do not have any problems on the highway and can get as much as 15 mpg in the city. I was getting only about 10 mpg in the city and about 17 on the highway.

There are trade offs, but I think overall, I balanced the equation with my tires and towing. If you do not plan on bigger tires, I recommend no lower than 4.35 (I think this is the middle ratio between 4.10 an 4.56)

good luck

 

Same here KTM, I also thought this vehicle with this big engine would have no problem pulling, we usually pull the boat with overdrive turned off, just to avoid the constant up and down shifting, I may eventually search out a 4:10 ratio to try to maintain some sort of mpg.
Cablecam, did you do it yourself or pay someone, where did you get needed gears and/ or how much $$was it?

 

Headers (may not be cost effective), cat back system, chip, intake. Will all hepl volumetric efficiency. So power will come up but so will mileage if you take your foot out of it.

 

I bought the gears from a local dealer who orders from Randy's Ring and Pinion. I tried ordering from Randy's but I saved $120 from getting them in town. The 4.56 is the max you can go for all 9 3/4 rears and all 8.8 without changing the carrier. (Saves alot of money) I kept the factory limited slip. The whole gear set up with a master kit ran about $700. I have a gear-head friend who specializes in transmissions and gears and he only charged me $500. The shop where I ordered the gears would have charged me $700. I could have saved some money and only ordered the seal kit without the bearings, but if something should happen like breaking a bearing on removal or install, I had it there. I also ponied up and added Royal Purple gear oil. It ran me about $80.00 for 6 pints. From all my research, this is the best stuff you can buy.

I noticed right away my engine did not have to work so hard to get going without any loads. I do have the K&N set up. Before the gear swap, the 5.4 sounded like the old 4 barrel carb with all barrells open. After the swap, the motor at WOT doesn't get as loud as it used to. I can only get the engine to work that hard pulling a load.

One more cool thing, I use to only get about 260 miles per TANK under normal driving. Now I can cruise about 330 miles. I have gotten as much as 350 on the highway by going the speed limit and driving wisley.

I hope this info helps.

 

I just took an extended trip and got 17.39 highway with AC on.

 

I just got a 2000 4x4 Expy with 5.4 litre engine. With 90%+ stop & go driving, on the first tank we got a 14.6mpg average. Probably half the time with AC, half without...

 

How much of a difference does it make running in 4x2 mode vs. AWD mode?

 

I thought lower ratio gears are good for gas milage ( 3.55 : 1 ) and higher ratio ( 4.56 : 1 ) are good for towing, acceleration, drag racing. I would think you would get less mpg with the higher ratio.

 

With the 305/70/16 tires and 3.55 gears, my gas milage was terrible. It was alot of tire for the motor to push. An equal ratio to the original 265/75/17 would have been about 4.10 with 305/70/16. By decreasing the ratio further to 4.56, I found an equal balance from city driving and towing and the highway. My city gas milage and towing gas milage increased sugnificantly, but the trade was highway. I do more towing and city driving than empty highway driving.

 

Thanks for the reply, that makes sense I was not thinking of the tire size you are running.

 

For a small block v-8 the 5.4L does just fine pulling my 7200lb trailer in MHO. Yah, I get 7-10 mpg towing, but whaty did you expect. Yah, it slows going up grades, but what did you expect. I was able to pull 6% 3 mile long grades at 40 mph. If you wanted to go faster you should have got a diesel.

 

Excellent suggestion, I will remember that next time........... Oh yeah, what size tires are you running? I will say it again, I am now getting 12-15 mpg with my trailer. Oh, and if I wanted a diesel, I WOULD HAVE BOUGHT ONE!!!

 

Sorry about the double post

 

That reply was aimed at KTM Racer. You, CableCam, sound like a driver happy with their vehicle and willing to make it so.

I just think it is funny that people expect a small block v-8 to pull like a diesel w/o any loss in gas mileage. I bet your rig looks sweet w/ those phat tires.