Heres the build:
1979 pickup
22R, weber, headers, 5inch skyjacker springs, 35 BFG/AT's, spool in rear

its been idling fairly high (1500, to 2000), I am still trying to figure out how to get it down. the carb is sticky.

Would that be reason enough to make my gas mileage be down around 10MPG????

 

definitely isnt helping. how do you drive?

 

Yes. Plus its an old truck. Carb'ed. Lifted, Large tires. Did you regear when you put larger tires on?

 

yeah, it is pretty old. oh, i forgot that I've got 4.88s in it.
do you think that I could dramaticaly change the MPGs if i got the idle down?

 

Ed H,
I drive mostly city. I would have to say that I am a hard accelerator. but didn't think it would go down to 10

 

all your mods and you have a heavy foot and a bad tune? be happy with double digit mileage lol. these trucks do not get great mileage to begin with.

 

See I've seen threads where people with 1st gens posted their gas mileage and with a stock truck in decent shape the norm seemed to be 15-17 in town and low to mid 20's on the highway.

I haven't had that same luck...but it's getting better. I'm at about 12 in town, 18-20 on the highway. And my truck is almost completely rebuilt at this point, so I'm not sure what the deal is.

There are all sorts of things that could make your mileage that bad. Bad or out of tune carb, timing off, dirty intake, engine running on bad compression, spark plugs/wire, distributer cap rotor....etc. Brakes dragging...

 

I wouldn't expect much more. I used to get 10 with my truck, it didn't matter if I was going 75 or 30, that was it. there's a lot of wind and rolling resistance with these trucks.

 

Does anyone know why these trucks got such bad gas mileage even when new? I was reading the "You know you drive a Toyota when..." thread (funny thread BTW) in the off-topic section of the forum here, and bad gas mileage was a common theme.

When I was a kid in the early/mid '80s, my uncle liked Toyota trucks like the one my grandfather had (late '70s 2WD) but would turn his nose up at the 4WD models. When I asked him why he would say they got bad gas mileage. So even then, when these trucks were new, the gas mileage was considered poor.

Is it because they added extra weight for the 4WD components and larger wheels/tires but didn't increase the power of the motor; making it work that much harder; ruining the gas mileage in the process?

 

Good question.



I know I easily got 25 highway and 17-18 in town with my '86 22RE. But really, I'll bet if we did a survey, you find a lot of people in our situation, but just as many getting high-teens in town, and low-mid-twenties on the highway.

I don't think they gave the 4wds more power, but they did get different gearing, I'm guessing. For their size, they sure could be getting better mileage, that's for sure.

 

Dont forget to calculate A BIGGER TIRE SIZE!http://www.miata.net/garage/tirecalc.html try this link I just found it and it made me feel better.

 

That is about right for me, I got 16mpg 95% city driving last fill up in my truck, and I have 31 inch M/T tires. I have yet to go on a long hwy trip so not sure about that.

 

high idle and 'sticky' carb sounds like you need to do a rebuild on it, or at least check for vacuum leaks so the idle comes back down. that would effect your mpg significantly.

you also need to factor in your mileage difference if you have not corrected your speedo/odometer for your tire size. you are actually traveling further then what your mileage says, so your real number should be better then 10mpg. other then that, these things are very underpowered causing a very heavy foot to stay up with traffic. i think i was getting about 15mpg mixed on mine with 33" tires and stock gears, and that's also not accounting for the odometer being off.

Al

 

You are driving a truck stressed by oversize tires and it has the aerodynamics of an outhouse.

Have you adjusted the valves? Tuned it up with quality parts? Spark plug gap correct.
5.29 gears would definitely help.
I have had 5 toyota trucks over the 20+ years, all Modded with 4WD, the mileage has always sucked.

 

. dbl post

 

My 83 is too bad, 35x13.5's, 4.10's, 20R, Weber 32/36 and 4" of lift. I rarely ever go over 3000rpm or give it enough gas to open the 2nd, no idea on MPG but I got around 370km to a full tank, it had a really bad exhaust leak before which dropped my mileage substantially for example

$15 gas with the exhaust leak would get me 70km
$15 gas sealed up with a full exhaust gets me 140km

I gave the weber a slight tune and fixed the timing aswell so those probably helped a bit, oh and having the right amount of air in the tires reallly really helps.

To help your problem it sounds like your choke is stuck on, what model weber is it? Water choke, electric or manual?

 

Yeah, I forgot about that. my truck is off by 5mph with my 31's so I am really getting a little more mileage then stated arnt I?

 

How much gas do you need to give it to open the 2nd?

I let her rip through the gears the other day for like the first time, the truck actually has some grunt when I drop the hammer on all 97hp haha.

 

My truck does great (great being a relative term..) from a stop. Really nice acceleration right off the bat. It's the highway stuff it doesn't like. Mountain passes, mostly.

 

my 82 2by would get 24 or so in town and up to 30 on the highway. Given that was with a tune-up and driving like a grandpa, but I digress.

4wd should get a bit worse, but I think 10 is a bit low, unless its all city and a lot of stop-and-go.