I drive about 35 max miles a day to and from work.My truck seems to just be drinking gas like its nothing. How in the world can i be burning a full quarter tank just from that? Lets just round out my tank to a 20gal.. that's about 5 gallons i burn in just that drive. Which puts me at about 6-8mpg. Uhhhhhhhhh wth? I drive slow all the time and rarely mash on it. The only thing different and can possibly think what is wrong is I just put a 3in spindle lift on my truck. That is the only difference. No bigger tires either. (Yet) Its had a tune up recently and air filter, fuel filter and new fuel pump changed out.I also doubt that my alignment can be throwing it off that much? But I could be wrong. Any thoughts???

 

Well, to start out, 33"x11.50 tires aren't stock. You haven't mentioned your gear ratio, engine, anything really.

My truck drinks fuel like it's free. Even with the wimpy 31" mud tires, but I'm sure the factory 4:10 gears have something to do with that..



GB :)

 

yeah my 4.0sohc 4x4 with 4.10s and 33/12.50s with 3" body lift and Im getting between 15-17mpg And thats with factory plugs at 83,000 miles and a fuel filter with about 15-20,000 miles on it.

 

^ ha thats pretty good. I'm getting 15-17 with stock 4.10 gears and 265's. Sometimes even 14.5 MPG. Fail.

 

4.0, stock 3.73 gears and 33s. I know thats crappy to have but I know it wont change my fuel that dramatically. Pretty much it seems to be more after this spindle lift. Could be bad alignment?

 

Driving nicely and getting 6-8mpg I'm thinking something is wrong.

My truck has 4.10 gears and 31 snows and I'm getting
average 17.8mpg
hiway 21.4mpg
city 15.6

 

are you remembering to correct the speedo? 30.5 inch tires to 33s is like a 8% difference in the speedo which in turn racks up less miles than you are really traveling. An nobody ever runs their tank dry. So 19.5 gal tank and in reality most owners fill up is 16 - 17 gal. So right there you are shorted yourself 2 -3 gallons. How many miles you getting between fill ups?

 

those 33's and 3.73 is like swapping to a 3.15 and adding 15-20lbs of rotating mass to the drive line of course its gonna effect your mpg hard even with a 4.0, which doesnt make peak tq to turn all of that till 3k, willing to bet with your slow non-mashing driving you always shift before that, so you could be bogging the motor out aswell.

give the maf a spray and see what happens.

 

Purge Valve and / or Lines

 

i have 4.56 and I'm getting 13 average. Not the greatest but its a truck they are built for work not gas mileage if you want good mileage get a fiesta

 

+++1 on that

 

How would the purge valve/lines be causing the problem?

 

vapors escaping and not being regulated properly

 

Where do I check these lines?

 

I go about 400+ miles in a week, and i go thru about i want to say a tank and a quarter in gas.

 

how big is your tank? because if its 19.5 u get like 25mpg

 

3.73s and 33s is your problems. I can tell you that right off.

 

Look first at the hose under the throttle body to see if it is dry rotted. It's hard to see at first. Your purge system is behind the driver's side headlight. There is a purge canister, purge canister valve, and a purge solenoid. There are hoses connecting these things that become bad and cause all kinds of issues including poor mileage.

 

im with him, 400 miles to the tank. Granted i have a 2.3L but thats besides the point

 

about 16 gallons.

 

Tank size is irrelevant for mpg calculations. You have to take the amount of miles driven for that tank alone, and divide that by how many gallons that you pumped into the tank. This yields your actual mpg.

Tank size doesn't matter because many people have different size tanks in their car. Also, you never actually run out of gas, so you can't use the tank size for the calculation. For my 20 gallon tank in my truck, I usually end up only putting a little less than 18 gallons in just after the light turns on.

 

This post isn't relavent to this thread really but I'd just like to say, I drove for 45 minutes at around 70mph(no slower than 68 and no faster than 71) the whole time and I got 19.6mpg. That is all.