fuel efficiency question

[mudeater34]

We have driven from Colorado to IL and back, and to NJ, NY, MD and back. Best is 16, worst is 13. We have a gnarley rack on top that I am sure does not help. We have tried driving faster, slower, cruise, no crusie, and have not seen much change. We just broke 40K on the '00.

[Dare2Dream]

Chopper, how on earth you get such good mpg? I've never heard such good numbers, you are lucky!!

[MrCrowley]

i guess sea level air density trumps the other factors except lead foot!

[VehiGAZ]

Talk about timing - pick up the Feb issue of Car and Driver magazine for an editorial on how driving habits & style affect mileage. The context of the editorial is about hybrid vs. non-hybrid versions of the same model, but that doesn't matter.

PS - warmer weather makes for better mileage, as most of us must have noticed. I don't know whether it is the higher temperature of the air or the lower density the vehicle has to push through, but this rule has been constant on every car I have ever driven.

[mbeach]

My mileage plunges dramatically in the sub-zero temperature range.
It is a combination of three things:
1. Denser air (at -30, the air is super dense!), the truck needs more fuel to maintain the proper fuel/air ratio.
2. Thick fluids in the diffs and transmission/transfer case. I have heaters on everything but the diffs, and I know that they thicken up when cold. This drags on the gears and creates friction.
3. Idling. This is the big one. I let our trucks run for 5 to 10 minutes before even moving them out of the driveway. This translates into 0 mpg.

As it stands, I am refilling every 230-240 miles. I really haven't math'd out the mileage, because I don't want to know.
It'll go back up in the spring.

[SPAZZ]

my VX new untill like 10 or 12,000 miles got 400 miles per tank then 300...then 200...that was like 10 miles per gallon highway and less city.

Then I modded the crap out of it and now it gets about 13MPG. I agree...I shoulda bought the biggest V8 Turbo Diesel Truck I coulda bought for the same price of the VX and got better mileage.
Replaced everything from Fuel filters, MAF, O2 sensors, Pcv, cleaned EGR, manifold gaskets, ECU, coils, etc..you name it.... even installed 4.56 axle gears. I have never got the original mileage back only inproved the down fall with mods.

The VX has been my worst financial investment, but my best hobby/mental investment

[VehiGAZ]

Don't forget about the confounding effects of local and seasonal differences in fuel formulations - that will introduce a significant variability in what mileage different drivers will get. Not to mention changes in formulations gas over time (for example, they used to put MTBE in our gas here in CT, then they switched to ethanol. I don't know which would give me better fuel economy, but I'm SURE the two additives give me different mileage).

Bottom line - don't get hung up on differences between your observed mileage and the mileage someone else says they get, because there are too many variables you can't account for to make it a useful comparison.