so i am puzzled. i have done everything i can pretty much think of to get better gas mileage and i am getting 11.8 MPG.
i have an 88' ex cab 4x4 SR5 pickup with the 22re automatic, 4 inch suspension lift and 33x12.5 M/T.
during this past summer i was getting 20+ MPG then i had what i thought was a blown head gasket...well it was along with a cracked head/dead timing chain. i would have done the work myself but i was in dire need of the truck asap so i had a reputable local toyota guy do it. new head, timing chain, gaskets and all the goodies. then about a week later i realized my freebee 32x11.5 A/T were starting to seperate the tread from the steel belts. so i gave in and bought new tires i decided on 33s because that is what i have always planed on, i was just waiting till the old tires wore out, and they did. i did a 450 mile about a week later and i was getting around 12 mpg
well it is 4 months later and i am still getting around 12 mpg
i recently did a tune (roter, cap, plugs, wires, and air filter), today i went in and had the cat tested to see if it was bad (by drilling a hole and testing for backpressure). and they said it was fine.
so i am wondering what is that is causing the rediculous change in gas mileage. cause 8mpg isnt a small drop. i have wondered if gears is the problem cause all the diffs still have stock gears. but would gears really make that big of a difference? to go from 12 to 20 mpg.
any advice would help
thanks
Justin

 

o by the way i forgot to add that i have almost no power from 50 mph on up

 

with 33's no regear?? damn thats a no no... the bigger the tire= the worse the mpg.
thats why your not getting over 50mph its killing your engine! four 33'' tires is big man!
check for vaccuum leaks too.


every week someone asks "how can i get better gas mileage"
tire size
lead foot?
where you drive makes a diff
winter gas vs. summer gas.
stop and go.
oil pressure
check gaskets to make sure he did a good job.

and.....
search
your
heart
out

 

Gears. Its not calculating the correct mpg at all either b/c your wheels arent turning and the speed which your speedo says.

Not to mention your truck is also pushing all the other junk around too. Your topper, suspension lift, etc.

Also you might be running to lean, advance your timing marginally and see if that helps. You dont mention engine size or model so its hard to say.. If you have a 3.0 12mpg is entirely normal with oversize tires and stock gears, 15mpg is what they run best and anything above that is a luxery.

 

did your tune up include the o2 sensor? that can kill your mpgs if it dies.

 

I would check to make sure that your ignition timing is correct.

 

honestly..going from a 32X11.5 At to a 33X12.5 MT is a BIGGER differance then you think....

 

ya i know it seems like everyone always asks this question that is why i was hesitant to start a thread about it.
but i do not really have a lead foot, but i dont drive like a grandpa.
and i have looked around and i havent noticed any vaccume leaks.

i have the 4 cy.
and i did do the calculations for the difference of the tire, stock tires are 28.3" tall (correct me if i am wrong) so i found out the difference in circumference and and that percentage, then applied that to my odometer

when i did the tune up i timed it right along with set the idle where it is supposed to be.
so i should lean it out then? even more

and no i did not do the o2 sensor, i didnt think of that. is there any way to check to see if the o2 sensor is bad or do you just replace it.

i was also thinkin about trying seafoam but wasnt sure

 

There is a test you can do on the O2 sensor to see if it's working properly. I'm sure someone will chime in on the procedure.

 

...and power. O2 is definitely worth checking out.

 

The change from 28.3"s to 33"s is 17%. That's a huge load on what I think is an already underpowered motor/auto tranny.
I think the tires are hurting you, not only the diameter but the width and weight of the tire. I would imagine turning a 12.5" tire is harder then a 11.5" tire since it weights more and has a larger contact patch. Good luck, gas ain't getting cheaper.

 

exactly^^ and if your on steel wheels...you MIGHT wanna switch to alighter wheel. every bit helps. Im trying to do everything in my power to get better gas mileage...

 

ya that would definatly be worth checking out the o2 sensor. but can anyone tell me a way to test it cause i am sure there is a way

the 11.8 mpg is WITH taking into consideration the difference in circumference from 28.3 to 33 if i didnt i would be getting even worse

 

Eee!! you are running 4.10's with a dinky little 4banger? Whoo, spend the cash and re-gear. You need to get 4.88's, your truck will have to work alot less to turn those big meats. Hell, even my 3.0 with goodies is not a big fan of my 33's

 

Wow, I didn't realize how different the auto and manual gear ratios are with the 22res. From 4crawler's site

W56 5speed
Gear Ratio
1st 3.954
2nd 2.141
3rd 1.384
4th 1.000
5th 0.850

A340F
Gear Ratio
1 2.80
2 1.52
3 1.00
4/OD 0.71

Not only do you have a much taller first gear which makes it hard to start from a dead stop, you also have a much taller fourth gear which gives you less power while cruising at highway speeds. Your fourth gear must be useless. Did these trucks come with a overdrive unit? If so, maybe just leave overdrive off at all times.

 

ya i definatly have an overdrive and before i gave it the tune up it was worthless, if i was going 70 and it shifted into 4th then it would quickly have to make it back down to 60 so i would have to downshift again.
but it does seem to be pretty much worthless.

but see the main thing is that if gears is the only thing to make me get better milege/power then i am just going to sell the truck because i was planning on selling it this summer anyways, i would rather not put another $800 into it for a few months and then sell it, plus i dont have $800 to spare

 

Check your timing, and mass airflow.

 

Your tires are too big, go find a used set of thirds and re-gear to 5.29 or something. Other than that, you could:
check ignition timing
check valve lash
clean out your throttle body (made a difference for me)
check you spark plugs
replace the cat
install manual hubs (less rotating mass)

Remember, regearing does what hp can't.

 

check for brakes sticking.

lift each wheel, and make sure it will spin freely.
dragging brakes can eat your fuel.

over-inflate your tires.
remove all dead weight.
alloy wheels are the best. good call on that.
you will actually feel the difference right away.
i had a pair, and will never go back to steel, unless i use them for winter studded tires.

 

I wouldn't overinflate the tires, they wear improperly and you have to replace them sooner. Not sure that spending $650-850 on new tires more frequently will offset the cost of gas. I second the regear though.

Chris