I got 17 in town and 20 on the highway with my brothers 94 dak extended cab4x4 with the 3.9. Origional everything with 200K. My buddy who has a extended cab 94 dakota 3.9 2wd gets 25 on the highway, now thats crazy.

 

96 3.9 2wd auto 3sp w/od &locking converter TBI Magna flow exhaust (sounds great!) andoversized tires, cause they were cheap but inexcllent condition(same revolutions equals more distance. It really adds up to maybe one mpg. Before I put on the new tires I would run 2200 rpm @ 75mph but now its between 20 and 2100rpm ///wasmix highway and city19-21 mileseasily before i changed the plugs and wires for the first time at 160k now between23-24. I have a big fat foot and atrue dislike for slow people SLOWER TRAFFIC KEEP RIGHT!
Keep your fluids good and the rest follows suit.

Forgot to mention... No tonneau Got rid of it to make room for my tool box lawn chairs andBBQ grill. HE HE HE

 

Just a brain teaser. Theoretically you get better gas milage without a tonneau and an empty bed with the tailgate UP! Proven Fact by the Mythbusters. Tonneau covers create more drag on the rear of the truck. With the open bed It creates a vortex that counters the airflow coming over the truck and channels it down the tailgate and that is where the drag is placed versus the rear window and the tail gate combined causing a counter flow (drag). As for me i have a tool box in the back and I think thats the worse thing for drag on a truck. well other than a windshield visor.

 

i can tell you that before I got the tonneau cover and installed it on my 96 dakota I averaged 17.3 MPG. After I put it on I averaged 18.6 MPG. Then I put on the electric fan and removed my fan clutch and I went up to b/w 19.1 and 19.8 but never could get over that. I recently started having what I believed to be spark knock and decided I would switch to 89 octane from 87 octane and on my first tank with the 89 I got 20.14 MPG.

So I'm kinda interested in knowing what model truck the mythbusters crew used to bust the tonneau cover gas mileage myth! I'm living proof with no nationally syndicated television station shooting for ratings backing me up. Just Scott, with a driveway and some tools!

 

I agree with this. I just drove 635 miles today in my truck. Before I put the tonneau cover on I was averaging around 22mpg on the highway with my 2wd 318. Today I averaged 17.5mpg. However, you also have to take into consideration the difference in temps too. It was 40 deg. when I left NC and it was 2 deg. when I got to PA. The colder temps will cause it to use more gas.

[quote]ORIGINAL: alterboy

Just a brain teaser. Theoretically you get better gas milage without a tonneau and an empty bed with the tailgate UP! Proven Fact by the Mythbusters. Tonneau covers create more drag on the rear of the truck.

 

My first fillup yielded 15.3 mpg, just filled up today and it's up to 16.3. I put an e-fan on it last night and I think i'm about to throw these bosch platinums out for something better.

 

How many miles does everybody have?...i have 174kon my sport x-cab

 

I have 88500 miles on my 1995 sport reg. cab.

 

260ish thousand ona 2wd 318 5 speed x-cab

 

I had 210,000 miles and I got 14 mpg city idk about highway