yea I normally only put $20 in at a time once the light comes on but I always fill it and test mileage twice a month or after a mod or repair is done. I do keep a log of mileage and I never got over 12.5 with the base tires (265's I think). My normal mileage was always around 10-11 mpg with the 265's. With the 35's it went down to 9-10 then I installed the k&n fipk and my mileage with 35's went up to close to 11. I got the check engine light a few weeks ago ( I posted about it when I got the light) ever since then my mileage has been back in the 9's. I just hope that if the motor does go it doesn't happen when my wife and son are in the truck.

 

Most of my driving quite the same, yet different, if that makes sense....

If I am not driving highway, then I am running it on the beach, 4x4 top speed at about 15MPH.

The fishing season is a bit done here in RI, so i will be able to get a true account over the next few weeks and will post.

 

You have the misfire code and they won't check the heads and valves? That doesn't seem right.

In my case, I told the dealer the idle seemed odd and he said he couldn't do anything without a code. 100 miles later I had the code, took it back, and they immediately checked the valves.

Maybe tires can affect mileage? But they ought to at least check you engine.

-Alan

 

Importkiller, there is something seriously wrong with your H3. I have nearly 26,000 miles on mine and get an average of 330 miles per tank full. This averages out to about 16.5 mpg. This is all in city driving. The best I ever got was 450 miles driving the PA turnpike. That is over 22 mpg. I would be bitching at the dealer big time for such ****ty numbers.

 

I'll just wait for the motor to die then push it in front of a freight train.... I'll get an 07 with the insurance money

 

Post head job.....drove her nearly 300 miles today and still 1/4 tank of gas left (average speeds of 80+)...drove like a dream, in fact had to rein it in a bit several times as she was raring to go! I am thinking the mpg will be about the same as it was pre head job...approx 15-16 mpg.

 

300 miles to 3/4 tank....good lord..I'm jealous

I got less than 200 miles on my last tank when the low fuel light came on

 

WOW, speakin of "Bummers" Yours really is.... KA-CHING!! KA-CHING!! I feeeeeeeeeeeeel for you! [sm=smiley6.gif] I'd be sittin on their doorstep with that thing because something really is wrong with it unless there are other underlying reasons such as aftermarket/add ons, tires, etc., or driving habits.....

 

I am no expert, not by any stretch. but i do know if you go up more than 2 sizes in tire size it is strongly recomended that you step up to shorter gears ( larger numarically ex. 4.11 is shorter than 3.73.) that might be the corp of your problem. the engine and tranny are having to work overtime to move the tires. more wear especally on the tranny. GM really should have put a bigger engine in the H3 in i personally think it is under powered. I drove one and was less than impressed with the power. Not trying to start any fights mind you. another thing to think about and you might already know this, but taller tires roll further, and there for your speedometer will read slow. so you will actually be travling faster than you think, and that might factor into the mileage. hope this helps.

 

there are alot of guys that I know running 35's on their h3's with stock gearing and still getting up around 14mpg+ so I doubt too high of a gear is my problem. And my mileage numbers and speed numbers are taken off my gps, not the speedo/odo...GPS doesn't care what size tires you have, it's always accurate.