gas mileage help

i have a 94 p/u sr5 98,500 miles 5spd 35"tires and im gettin crappy gas mileage probaly like 12ish city  i need help wat could it be i have a k&n cold air intake. ngk plugs with 3500miles on them. what could i do to help. ive been reading forums with people saying there getting 15-22 with there lifted 4 runners and tacomas with like 31-40" tires but with 22re's also so i guess that helps alot but still wat could i do to improve my gas mileage besides things like replace the o2 sensor clean air filter ,plug wires, fuel filter rotar and cap?  

I think that some of those claims (especially the ones of 20 MPG and more) are snake oil. You should do better than you are though. A K&N intake will not do squat for your MPG. It is a myth. It started with carbs as in theory it could slightly lean out mixture on a carbed engine but it will have no effect on a FI engine which is mixture controlled. Also while cold air may add a few HP WOT, it increases pumping losses at cruise which means a bit more wasted fuel. One thing you can do to improve MPG is regear truck because right now it is laboring badly with 35's and stock gears. When you lift a truck and run big tires the lift increase aerodynamic drag and tires increase rolling resistance and this takes more power/fuel to overcome. But, if you do not regear, the engine is now turning at a lower RPM at same ground speed as with stock tires which means it has LESS available HP (HP is a product of torque and RPM) so you now need more HP to cruise and less to do it with so engine labors and is forced into a inefficient mode of operation and MPG suffers even more. Deeper gears restore balance and make more HP available and lets engine work more efficiently when cruising. I would never lift and run big tires on any 4x4 without regearing but many do and suffer from it in poor MPG, reduced performance and shorter drive line component life.  

Did you regear when you went to 35" tires?
If not, the engine is not operating in it's power band, which means a loss in power and poor fuel economy.

Additionaly, both your speedo and odo will not be accurate, so your MPG calculations will not be accurate either.

Instead of wasting money on cold air intakes, etc, spend some $$ on gears, or go back to smaller tires.

And to answer your next question, figure $450-600 per axle for parts and labor.  
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seen in FOUR WHEELER magazine July 2006 and OFF-ROAD magazine Feb 2007

'84 4Runner SR5 -
ARBed 5.29s F&R, 4.7 & 2.28 t-cases, 2" drive train lift, AP hy-steer, BudBuilt x-member/skidplate, 36" TSLs, 30 spl Longs, Chevys, rears up front, winch, yada yada ...

'80 something Toy P/U -
Buick 231 V6, Holley 4 bbl, Weiand intake, Downey headers, TH350 L/U w/700R4 low gearset, dual tanks & batterys ...

89 4Runner SR5 -

I get about 14-16.5 mpg in my 94 Toyota 3.0. It has 186000 miles on it, 33x12.50 inch Truxus, and has survived being flipped doing 70 on the interstate. I have a K&N filtercharger, Flowmaster exhaust and a homemade high flow cat converter (a pipe and hammer help accomplish this). Of course this is not legal in counties or parishes with smog testing. But there is hope. Check into a high flow converter and also check with Jet performance and see about getting your ECM upgraded. All your mods are not being recognized by your stock one. They can program in your mods and help to get more power and perhaps better fuel economy. And keep your air pressure at the proper levels while you are at it.  

wow i learn something new everyday!  

I am running 35's on a stock 93 4wd with 22 RE 200,000+ miles K7n filter and mass air flow sensor up one notch richer improved milage by 3-4 mpg with no other mods.JUST remember to shift and not lug with taller tires.  

Gear gears gears!! You guys running 35's on these small motors need to regear! You are losing mileage, performance, and drivetrain life by not regearing.

Man, I'm starting to sound like Sno... lol  
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Long Travel 4WD - The best of Both Worlds

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rflemedic:
I am running 35's on a stock 93 4wd with 22 RE 200,000+ miles K7n filter and mass air flow sensor up one notch richer improved milage by 3-4 mpg with no other mods.JUST remember to shift and not lug with taller tires.

I love this one, MAF sensor one notch richer...  

I gotta tell ya but I agree with sno.20 mpg in lifted trucks with 4 bangers and mud tires just isnt going to happen.Also shift and dont lug.My lil' Nissan(take that yota lovers ) gets 15-23 mpg(15 in winter,20-23 in summer.But thats with idleing to warm up.)Thats with a v-6/auto,and 31 inch road runners.  
Dying ain't much of a livin'
From my favorite movie.
Trucks...
1989 150(200k) 33 inch hawgs and a blown 302.
1995 Pathfinder(178k)and still going with 31s.189k and blown tranny.
Bikes.
2004 Yamaha TTR 225,barly used.
Kawasaki 750 (26k) Not ran right since carbs rebuilt.
!972 Yamaha mini enduro.The niceest one I've ever seen thats never been repainted.
New 2002 f150,fx4,5.4v8,after market tranny coolers and unirol tires.

On my K3500 plow truck, I loose between 2 and 3 MPG just changing from street tires to very aggressive studded snow tires for 4 month of same relative size. Big tires would be even worse. And this is before I load it down with ballast, salt, spreader and plow and then MPG can really tank. Sometimes I can use more gas in a day than many use in a week or two.  

Well get rid of the land yacht and get a Toyota, then you'll get decent mileage like the rest of us.  

I run 36's with proper gearing, and I get 20+ MPG on the highway, and that's with a worn, carbed 4 cyl.  
--------------------
seen in FOUR WHEELER magazine July 2006 and OFF-ROAD magazine Feb 2007

'84 4Runner SR5 -
ARBed 5.29s F&R, 4.7 & 2.28 t-cases, 2" drive train lift, AP hy-steer, BudBuilt x-member/skidplate, 36" TSLs, 30 spl Longs, Chevys, rears up front, winch, yada yada ...

'80 something Toy P/U -
Buick 231 V6, Holley 4 bbl, Weiand intake, Downey headers, TH350 L/U w/700R4 low gearset, dual tanks & batterys ...

89 4Runner SR5 -

fourwd1:
Well get rid of the land yacht and get a Toyota, then you'll get decent mileage like the rest of us.  

I run 36's with proper gearing, and I get 20+ MPG on the highway, and that's with a worn, carbed 4 cyl.

Maybe on flat ground with a tail wind or drafting behind trucks and keeping speed down too. Physics does not support it otherwise.  BTW, my truck is not a daily driver as it only has 45K on it and it is 9 years old. I drive 4 banger cars the rest of the time mostly that have to have a bad day to average 20 MPG and one of them has hit over 40 MPG a few times and I bet that that one would leave your Yota in the dust on a open road too. (I know it would with ease) Point is when I need a truck I drive it and it can get out of its own way even when it is grossing over 9K. When I do not need a truck it stays parked.  

Well I have 4.88 gears in my Yota. If I run 31's it still gets about 18- 19 mpg at best. But then again mine does have some issues. It eats sparkplugs about every 6 months (scorched). Basically they are not very efficient motors. If you want efficiency get a Kia or Hyundai or some other glorified go kart. I will stick with reliability. Oh and I turn over 35x16.5 Boggers with ease. These motors are more powerful than you think, but you are right about the wear and tear to the drivetrain. Used to run 5.29's and that was perfect for the Boggers.