You sure this wasnt a bronco 2 ?

 

I know 1 guy who is retired from Ford. He get 29-33 mpg with bronco II 2.9L with 5 speed. He use for plow snow. Now he is get 26-28 this year. Could be gas turn to garbage and cause terrible mpg compare couples years ago.

 

Broncos are fun.

They can actually do better on mileage than trucks because of their shape. Vans are even more aerodynamic. My '94 has a 5.8, C6, and 33" tires and I get about 16-17mpg. Its a complete beater. Has 4.10 gears, headers, dual exhaust, elec. fans, and a big cone filter. I'm sure with out those mods it would be like 10-11. It still needs a tune up really bad.

I also had a '94 F150 that got over 20mpg. It was a long ***, heavy truck with a 5.0 auto. I deleted emissions, opened up the stock exhaust more, bumped timing, electric fans, blah blah blah... For all the effort I put into it, I got 6-7 more mpgs than stock. I may have spent around $250 doing it all. I did all the same things to my '95 4x4 F150 and took it from 13 to 20mpg.

If I had it all my way and had some more time and money, I could probably get the Bronco to the mid to high 20s in mileage.

 

are you taking in odom difference running the larger tires? also how are you able to make the electric speedo work on both your 94 and 93 broncos while running a C6 and 9" rear diffs?

 

'93 never got finished. The '94 has a chain sprocket welded on the pinion yoke and the sensor is mounted beside it(came to me like this). I checked it with a GPS and its within 1-2mph. Most vehicles are about the same(old and new).

 

I had a 86 with the 5.0 and AOD. It got 20-22 MPG. But, it still had all the emissions crap on it. Well no cats. It had longtube headers and cherry bomb mufflers that came out in front of the rear wheels. I rebuilt it, then blew it up. Yay me!

 

I have an '86 bronco with the 5.0, efi, 4 speed no OD tranny. 240,000 miles. I had no lift and 32" tires. I'm throwing on a 6" and 35"s, and haven't ran my mileage yet.
The engine is bone stock, other than a magnaflow header back exhaust.
Anyhow, I was having trouble passing emissions, so I did pretty much everything that could be done. Oil change, premium fuel with additive, fuel filter, cleaned EGR, air filter, plugs, wires, caps, rotor, o2 sensor, timed to 14 BTDC, (my freak Bronco runs best there, dont lose your mind) and did an intake bath with seafoam. (I would definitely suggest this on any vehicle with 50,000+ miles. I've done it with every vehicle I've had, and it's been very beneficial)
Afterward, even with the steel wheels and 32"s, I've never gotten under 19 MPG. I usually get 22 or 23, but never better than 23.5. I'm sure that'll die with my lift and 35"s, but it's my crawler, not a Prius.
Just know that it can be done, I'll help with any questions you have

 

your Odometer will be off with that size tire so how are you acuratly getting these mileage figures?

 

I hesitate to tell anyone they are full of kaka, but I have never heard of any full size Bronco with a v-8 getting better than 20 mpg. I have actually never heard of a full size Bronco with a 300 get better than 20 mpg. I'll even go so far as to say my Dad and uncle both had early Broncos. Dads was a 72 with a 302 and a 3 speed and it never got better than 15 mpg. My uncles was a 72 with an automatic and as far as I know it never got more than 15 either. So as I said I hate to tell anyone they are full of it , but I believe you are full of it.

 

I can see getting 20mpg from the 5.0/AOD combo in a full size truck, but it's only gonna do that at a steady cruise speed and that speed will get you run over on any freeway in north america.. so it's not really a highway speed it's more of a back country 2-lane blacktop speed.. think 50mph. The reason I say this is because I have seen close to 19mpg(hand calculated) from my truck at a steady 70mph highway cruise and that's a little to fast to be optimal for a vehicle with the aerodynamic profile of a tool shed.

 

I'm with Conanski......maybe with a truck, but I think it would be pretty hard and wishful thinking for seeing over 20MPG in a full-size Bronco. You just can't make a "brick wall" aerodynamic enough!! And driving 30-40 MPH everywhere might get you in trouble..........or shot!
Here is a database for EPA ratings for vehicles. FORD BRONCO 4WD Gas Mileage - Fuel Economy Database