Bad Gas Mileage Problem

I have an '07 4.0 V6 with a K&N Cold Air Intake with a 4" Bilstein lift with 33" Toyo Mud Terrains. Whenever I get to empty, way past the light, my truck fills up to 18.7 gallons. Apparently the truck has a 21 gallon tank, but I am getting about 230 miles out of a tank. I do not know if this is normal for this set up or there is something wrong that needs to be fixed. When I do the math I'm getting about 12 MPG. I do run my A/C a lot, but I would not expect it to take that much gas. I would really appreciate some help.

 

Here is where it is going down:

K&N Cold Air Intake.
4" Bilstein lift
33" Toyo Mud Terrains
Running the AC a lot.

The biggest hits are the large tires and 4 inch lift. Cold air intake commonly throws off the Air Fuel ratio.

 

I don't want to sound insulting but seriously what do you expect with 33 inch mud tires? The AC use isn't going to affect your mpg's much, I generally keep mine on all the time and still get 18 mpg's combined.

If you want to figure out your mpg's better you need to figure out how far off your odometer is due to your tires. Use highway markers or a known distance and try to figure out if your odo is reading true, most likely it's not.

 

What they said.

 

Don't feel bad man I get 13 to 14 on average

 

That is the price you pay for looking cool driving down the road. MT's, really...

 

I get 16.5mpg with my 285 70 17s but mine aren't mud terrain, I don't have a K&N but I do use the hell out of my AC and I am 4x4 3.4 L w/ a full 3" lift

 

You swapped a 3.4 for the 4.0?

 

Hence the bad gas mileage

 

And lack of power.

 

http://www.tacomaworld.com/forum/tirecalc.php

 

Try this: fill up your tank at a gas station early in the morning (when the gas is still cold) and go with the slowest filling opinion your can. You should get at least 10 percent improvement.

 

But then there goes the gas mileage again. Catch 22.

Umm. What?

 

I have the same Toyo 285/70/17's and get 17-19 with my A/C on all the time...

 

LOL whoops that was on my 95 yes I have a 4.0

 

With all that going on you might as well be pulling a 4,000# camper. That's about the kind of mileage I get with mine pulling the camper at highway speeds with a bone stock truck.

 

That applies slightly to diesel/heating oil, but gasoline? Explain.

 

So what is your commute?

Short commutes mean low mpg, heavy stop and go same thing.

 

The tanks are pretty deep the fuel will stay at ground temps most any time of the day 10% is wishful thinking at that rate you had better use it fast or it would heat and 10% would end up on the ground. Cars and trucks don't get filled by the pound only big aircraft. Fuel weight is usually measured at 60* If you do the math cold fuel will yield about .1 gallon in 20 compared to 87* fuel or about 2 miles per tank not miles per gallon 2 extra miles per tank.

 

Thank you all for your responses. I was not expecting to be getting 20 mpg with my set up, but I was expecting at least 15. I am not sure if my speedometer off because I've tested it and one friend said its accurate and then I had another friend tell me its not. I never thought that the odometer would be off because of my tires though. I am going to try Fuelly and see my results, but thanks for all your help.