If it truly does weigh 3084lbs I can maybe see that, my truck would knock on 20MPG freeway weighing a good 1300lbs more.
FWIW I ran a Mopar 5.9 PCM on my 5.2 for a long time and never noticed any fuel mileage change, and the wideband did not read rich either.

 

I get a solid 20 MPG from my 93 318 Clubcab Dakota that I converted to a 5 speed manual NV 3500 trans, a stock 94 318 manual trans computer and 3.55 gearing (I have a Sure Grip here that I have yet to install) and that's with shorty headers a TB Spacer (put on by PO so I wasnt the one that wasted any money on that paperweight/ but it was already there so I left it be)
and that's with a known-bad plenum gasket too.
The worst I have seen from this truck so far has been 17 MPG; coincidentally also the best I have ever gotten, out of my other Dakota; a 94 reg cab/shortbed w/a 6 cyl and auto trans; all stock except I removed the cat

 

i was confused at first two so i asked a professorial mechanic/ dyno lab owner he said the the onley thing that made sense to him is that cause my truck is gutted i have a 5speed 2wd tranny and the 4wd rear end with 390s for gears that my truck dosent have to struggle at all to move its self. but thats what he said idk if that makes any sense to you guys. and my truck is a reg cab short bed as well.

 

All I can say is lol. Also I didn't realize that a mechanic is a professor. :-P All kidding beside I would suggest internal upgrades like cam change or stroke it, there is also a very good article on car craft to hotrod these little engines for about 3500 bucks. I suggest to view it, it doesn't hurt.

 

Do you have a link to the article?

 

if same article I am thinking about I have it printed off somewhere...360 magnum - wish they kept it fuel injected though

 

I was getting 22mpg driving cross country with the 3.9, 5 speed, 4x4. I don't see why he can't be getting that kind of mileage.

 

This article?

http://www.popularhotrodding.com/eng...e/viewall.html

 

All kidding aside, it does actually make sense for mileage Close to that, 24 in my opinion might be a little exaggerated but above 20 I can believe, with it being gutted a good few hundred pounds and being a stick with high rear gears, not to mention a short cab short bed, it's not that heavy of a truck to begin with.

 

Ya sorry for the wait there guys, haven't been near a computer for the whole weekend. Getting back to it, ya they aren't using a EFI, though that doesn't really have to stop us eh. Here is the article also thanks for finding another article on the subject JGC.

http://www.carcraft.com/projectbuild...e/viewall.html

Also you could always check the good old youtube, to see what other dakotas are running.