I'm sure it's been covered a thousand times but I believe I have an issue with my 3.0. Yes I know they don't get great gas milage in the first place but 11 mpg is bit of a far stretch for a motor that is supposed to get around 19. I got 190 miles out of my last tank on PREMIUM fuel.

If anyone knows what going on or has a suggestion that would be awesome! Thanks

 

Any CEL's?

 

Any codes? It appears you have a 4runner by the picture, is it an auto as well? I know nothing of 4runners and autos but from what Ive read they don't do to well on gas. I had a friend that had a pickup/auto and his didn't do well either. I would loose the premium fuel, I don't think it will help it run any better, at least it didn't seem to make any difference in my pickup and it sure costs a lot more. How about a recent tune? Any vacuum leaks? I set my timing at 12 instead of 10 and that helps a little, might try a little more than that and see. Some run a lot more. My 90 v6 does quite a bit better than what your getting, but its a pickup/5spd. I don't ever fill it up, I buy 20.00 dollars worth, that gets about 8.5 gallons and I usually get 150 miles out of that. Depends how much I use the air conditioner. Don't know that a 4runner will do that. Good luck with it.

 

Thanks for the info. I've only had it for a couple of weeks and the check engine light came on not too long ago so I'll check the codes and see.

 

If it were me....I'd run a bottle of Techron, or similar quality fuel treatment thru it. Then, change the oil. Then, change the fuel filter.

You did not post other details; mileage, big tires etc etc.

YMMV.

Party on.

 

My bad! And thanks for the info. It's a 1995 with 177k on the 3.0. Has 31" mud tires.

 

Pull the code first. It may point directly to the problem. A 4runner auto should get around 15-17 mpg, a 5-speed 17-19. 11 is definitely too low.

 

I'll do that and let yall know! Thanks for confirming that it is too low lol I knew I wasn't crazy.

 

the tires will greatly effect it. periodically check the wear pattern. ideally, you want it even, but might do better more centered. i historically got 10-11mpg with 265/75r16's, but i know that is in huge part to the engine sluggishness and shift points. i just adjusted the afm to let it run closer to stichiometric, and gained a whole bunch of response and power. unfortunately, i'm in the middle of a 350k mi body/elec. overhaul, so no numbers to post yet, but i know the programming in these is garbage and optomistically geared toward low fuel usage, without consideration to power demand. bottom line: a little more enrichment not only prevents premature "low octane tables" to be enabled, but provides the ability to stay in a higher gear, using less fuel than lean burning at high rpms.

 

forgot to mention: cooper STT lt center cyped. same tread pattern used on toyo and others, and pretty sticky.

 

So would you recommend and ECU tune and different gearing?

 

if you have the$$$, then why not?, but you want to know the gearing long before you go that route, and rely on experience from many..... but i spent years just playing with the etc button, and adjusted the vafm. i'll try to remember to upload pics later, but i basically ended up loosening the spring about 4 notches, and found it rested between 2 factory score marks on the ring. for years i always thought to myself that the factory trans tune was meant for an engine with more torque, so that's what i gave it. as far as tuning goes, there are many tables, but the ltft is dependant on the o2 readings and octane. if you don't know what that means, it basically means that by manipulating the afm you gain throttle response, loose premature low octane modes (which will waste premium fuel) and advert unnecissary kick-down, yet, if it should be too rich for long-term driving, the 02 sensors will cut the fuel back while cruising. it's a free mod, and reversible, as long as you mark the factory position with a sharpie. it was said toyota that made me really see the ironic fact that lack of fueling can lead to wasted fuel consumption/ via rpm's. and again, never underestimate the rolling resistance of your tires. 5psi under can kill many mpg, no matter what you drive. speaking of, just what "mud tires" are you running?

 

I'm running these. Mud Claws.



They have pretty aggressive tread. And if you could post those pics of that mod you did that would be awesome!

 

lets see if those work. you can see the tang that holds against the teeth, you can tighten it (leaner) by turning the disk clockwise, but you have to push the tang out to let it turn ccw. it's not a whole lot of spring pressure on the ring, but be careful not to let it unwind freely. just use a screwdriver to let it slip one tooth at a time. you want it warmed up good to operating temp first, then go one notch at a time until it revs crisp without raising the idle. as you can see, mine landed on the 2 marks that were already there from the fatory. if you don't like it, you can always put it back.
on a side not, i did gain better milage running premium. if you don't, i would check the ignition timing, o2 sensors and general ignition system component wear. your fuel gauge work? i don't know about this engine, but most do an octane check at each fuelup and sets timing retard if the knock sensor senses detonation.

 

So did you turn yours ccw or cw?

 

lossened the tang so it went ccw. i came up on old school carb tuning, so i learned the feel..... which is a certain learned talent, but you want it to rev crisp without lag, but you don't want it to sit rich at idle and ramp up on it's own.

 

Hell, I've been getting 9.5 mpg and haven't been able to improve it. I do have 32" tires (auto trans) but the 9.5 mpg does reflect a 14% increase (i.e., gallons/odometer miles = 8.3 mpg).

 

I too own a 90 4runner with a vz3. Regardless of age, non have great gas milage. Best things to do regarding this would be:

Replace engine air filter
Clean the throttle body
change oil + filter
balance tires
run a fuel treatment like Vavloman mentioned, techron or B12

You wont see much but you should see an improvement.