I was wondering what most of you get as far as in town mileage.

I have an 86 F150 4X4 with a 3-speed (I don't believe I have OD). When I am in town I get about 6-8 mpg. However, over Christmas I drove 300 miles to my parents' house and averaged about 25 mpg on the highway. I understand that highway driving should be more efficient than in town, but that seems like quite a difference.

So, my question is, does this seem normal to everyone, and if not, what's eating my gas while I am in town?

Thanks

 

Hey I have an 86 f250 with 302fi, and i really don't get very good gas milage. i usually in town burn around $15 for 25km's now that varies on temp outside as well. But for a 86km highway drive i burnt $55. I think a carb wouldn't burn more than what I am now. or maybe i'll just burn it.....it seems outragous, but i'm gonna try a coolant temp sensor to correct my prob...well hope!!

 

ok, I've been seeing alot of kilometers popping up here, so I'll convert my mileage (do they call it kilometerage?)

6-8 mpg in city -- 9.5-13 km/gallon -- 2.5 kilometers/liter

25 mpg highway -- 40 km/gallon -- 10.5 kilometers/liter

since gas costs such a different price everywhere, it doesn't really matter how much it would cost me for a 96km drive (here in southwest virginia that drive would cost me about $4 on the highway, or about $17 in town).

 

if your shifter just has 1-2-d-n-r then its a 3 speed(unless theres an OD button). i can believe the 6-8mpg in the city but 25mpg on the highway?? something doesnt sound right there, my 98 camaro averages that. what speed are you going? what rpms is it at? i average like 8-9mpg mostly highway. if you went 300miles on a full 19gallon tank its only 15mpg, cant see how you can get 25mpg, you woulda had to have only used up 12 gallons to get that. i mean these trucks stock advertise 11mpg highway with a 3 speed. what motor? fi or carb?

 

I have a 4.9L with a one barrel carb. I do not have overdrive. I have big 32 inch tires on the thing. I HAD the duraspak 2 ignition, but I think that might have been disconnected. There was a fire in the engine compartment and when the truck got rebuilt, I think we just bipassed the duraspark cause it was too tricky. The engine is rebuilt, and has maybe 5K on it. The tranny and rear end and transfer case are all original with like 150K on them.

Before I left town, I filled both tanks (a 15 gallon and a 19 gallon). I used 13 gallons to go 272 miles which now that I look at it is 20mpg. So, that's 20 mpg with BOTH tanks full. I never refilled, and I never switched tanks. I got the exact same on the return trip.

I averaged 55 mph. There were 3 or 4 stop lights on the trip, and other than than a steady 55mph. I am not sure the rpms, I can check but I really don't remember.

So, yeah, 20mpg on the highway. When I was at home we got dumped on with 14 inches of snow. I drove around with the thing in 4WHi and averaged 4mpg while I was there.

So, 20mpg IS possible on the highway. that's why I think that something is goofy with the carb, since my in town is so crummy comparatively. Or, maybe the tranny? Diffy?

 

I got 16 MPG a few weeks ago in a little test run of 40 miles running at 65 MPH hauling 2000# of fertilizer in regular drive. This was after replacing MAP sensor and O2 analyzer and I was pleasantly surprized. Howerever I checked it last week after running around town and back and forth hauling big loads of firewood and I only got 11 MPG. My truck is a 1986 4x4, FI 302 with 4 speed OD. I've never heard of anybody getting in the 20's with a 302 automatic transmission.

 

ok yeah that sounds a little better 20mpg going a steady 55mph on the 300I6 makes a bunch more sense.

 

so, 20 on the highway is reasonable, or even pushing really good. Is it normal then to only get 6-8 in city? It just seems like such a disparity in efficiency. I mean is there something I should be checking (like MAP or O2) to try and push up my in town mileage?

 

carbd motors dont use map sensors or o2s, that i know of anyway. do you granny it?

 

I don't trust any mileage figures unless they include multiple fillups. Too many variables like filling up on an incline, decline or a pump handle that shuts off early. How many times have you driven off from a fillup and noticed the gauge is not all the way over (past full)?

 

Do I granny it? I can get her up to 35 mph in under 5 minutes!!! Seriously though, I do indeed granny it. I live 2 miles from where I work, and I NEVER get above 35, and most days my top speed it about 30, and it usualy takes me a little while to get it up that fast. I am sure I am cursed at daily for being a 'sunday driver granny'. So, yeah, I do granny it.

 

lol yeah right you have a lead foot!! joking. something is not right with the tune then cuz my friends 300i6 screams off the line.

 

actually, in the early 80's fords (mine's an 84) they started using map sensors, o2 sensors, tps sensors, and a buncha other stuff....i'm slowly getting rid of all of that....it's gonna get a different carb with NO sensors on it, and the computer and all it's BS is gonna go bye bye...but yes, they did try to run a computer with the carb'd 300-6's....

right now, i average about 8 mpg no matter what driving i do, which runs out to about 200 bucks a month just in fuel, and i only live 7 miles from work...but, i also know that the carb needs rebuilt, the rings need redone, and if i kept my foot outta the throttle, that just MIGHT help my fuel useage a little bit....i run 70-75 on the highway when i'm goin somewhere, which puts me up around 2800-3000 rpms...not exactly the best rpms for saving fuel...i'm planning to swap in a zf 5 spd eventually, which should drop my highway rpms to around 2200-2300, which would be much better for my mileage...

MontanaFord

 

Ok, well I suppose then I might try to play around with the carb. The truck does smell alot like gas when idling. Maybe I should just run a tube from my tailpipe to the warm air intake of my air handler??? kidding.

So, I have NO IDEA how to tune or rebuild a carb. but, I reckon that's why God gave us chilton and Haynes. So, I'll try that and let you all know what happens. Never done a carb. but, my dad gave me a spare carb for the truck (I think he built his garage out of spare 80-86 F150 carbs -- heck, I think I was almost named Ford 150 Gray).

but, I'll keep you all posted on what I can push it up to in town. I just changed my plugs and oil the other day. the old plugs were a little black, and the smell along with the black plugs makes me lean to a rich mixture. So, I guess it's time I finally learned how to rebuild and tune a carb.

Thanks for the help everyone. If anyone knows a good site or book on carb tuning/rebuilding, let me know.

thanks again.

 

I've got an 81 F100 with a 4.9L inline 6 and a single barrel carb. BEFORE i rebuilt the carb I was geting around 16 MPG...buuut of course I can't leave well enough alone so i decided to rebuild the carb. NOW i only get about 12mpg. Anyone know why its so much lower?