23 MPG from '99 3.4 V6 with 169k miles...really?

So my new 1999 rust buggy with the 3.4 V6 and manual tranny and 169k miles is getting around 23mpg. That seems really high for a vehicle this old with this many miles. But I've filled it up twice and checked it carefully both times. First was 23.4 and second was 22.5. Looks like this model with these specs was rated around 18 mpg hwy when it came out. What gives? Not complaining...just bewildered.

 

Do you have a lift? Any mods to your truck? What kind of driving do you do?

 

Yup, I was getting that mileage with my 97 with 175000 on it. Just great engines.

 

No lift or mods. I drive 90+% highway miles. Round trip for work everyday is 110 miles.

 

what size tires are you running?

 

Hmmmmm, 23 does sound kind of high. The most I could ever squeeze out of my '99 was 20.

 

Thats pretty damn good. Milage has nothing to do with it. When my truck was stock other than a lid, deckplate mod and a magnaflow muffler i was getting 23 mpg. Now that its lifted, oversized tires, sliders and no lid im getting 20-21 mpg...mind you i have an auto.

 

The truck isn't nearby at the moment, but I'm almost sure they're 235-75R-15.

 

I'll be filling up again tomorrow, and I check the mileage on every fill-up. If this third tank turns out to be in the same mpg range, I'll know that I've just got a nicely tuned, well-running, high mileage machine.

 

That will definately help out the mileage!! those are small tires

 

There's no significant variance from stock tire (225/75/15) diameter (28.9" versus 28.3"). This would account for about a 2% increase in apparent mileage due to odometer error, but that doesn't explain a jump all the way to 23 mpg.

 

Well I guess it is legit. Third tank was 22.8 mpg. Looks like I've got a winner. Now, about that rust...

 

Maybe it's the lightened frame that reduced the weight to get that kind of mileage

 

Perhaps, but wouldn't the dangling pieces of rust increase the coefficient of drag?

 

Only until they fall off... then it's all about power to weight ratio

 

Guess that means I have to cut down on the Whoppers and Burger Shots from Burger King.

 

As the metal rusts away there's less and less 'drag' from the earth's magnetic field ...

 

Yes, but the pits, pockets, and holes left behind create additional drag. That's probably a good 2.5% reduction right there...in fuel economy, not body mass.