gas milage problems

[H3mainer]

just filled my tank and had a 13.5 average lowest in a while ussually hovers around 16
anyone have any advice as to things i should check? air filter fuel filter?? im stumped. driving has all been the some city some hwy no hard offroad or hills. also, Does Anyone notice and milage difference running premium fuel??

[HummerNewbie]

How many miles do you have? That is right about where I am averaging with 3,500 miles on mine but that mainly has to do with my driving. Almost all city with probably 30 miles a week of highway which I am running at 70-80 which does not help. Not sure what you need to check but are you positive that you didn't drive it harder than normal on this tank? Don't think you will gain anything going with premium that would be a benefit worth the added cost.

[hmrlvr]

I run higher pressure in my tires (thanks for the idea Neo) and seem to get better mileage. You could try that. Maybe their low???

[H3mainer]

what pressure are you running?if you dont mind me asking
newbie i got 14000miles

[HummerNewbie]

Anything change recently that could cause the drop in mileage if you did not change your driving habits at all? I would definitely look at your tire pressure. Don't know if the mileage will drop noticable if you are on the low side of the pressure range though. I am hoping to start seeing an increase in my mileage over the next several thousand miles.

[Steve - SanJose]

Probably just a change in the type of driving or an incomplete fill up 2 tanks ago. No need to become concerned unless 2 or 3 tanks are low mpg with your usual driving mode. You're not noticing any power loss or other engine problems?

Running premium will not have any impact (except draining more of your money)

S.

[RubHer Yellow Ducky]

You didn't state the miles on the H-3. Yes its true tire pressure can play a big part. I running Factory Stock Goodyear Wrangler RT/S 265/75 R16's. The decal by the drivers door says max pressure 30psi yet the tires say 44psi.I started running 40psi and my mileage has increased some. Also in the U.S. we just changed to the Summer Blend of gas. Not sure if that can effect your mileage but maybe f5 or other more knowledgeable (not bs'ers) can address that. It there is an effect it will happen to all of us.

Hope we find your answer...

RYD

[sltbluh3]

I was getting 18.6 mpg I switched over to synthetic oil I'm getting 19.5. I'm running 35 psi in tires... definately driving style can swing mpg by 2 maybe 4 mpg.... I run 36 miles 1 way to work 20 country mile 5 major stop and go the rest interstate

[RubHer Yellow Ducky]

sltbluh3
Hummer Novice

If your getting a TRUE 19.5 mpg average your way ahead of the game, EXCEPT for our friend H3HUMVEE who claims 20+ mpg AVERAGE city/hwy...

All we ask is that you repeat it 3 times in a row and after that take our math test...

RUD

[f5fstop]

Premium won't help. Ethanol fuel will lower your mileage, not sure what Maine requirements are.
Tire pressures, if an off-road package, should be at 35. Too low, decreases fuel mileage, too high is bad for the tires, and will not give that big of an increase.

[nmikes]

You also could just of had a tank of bad gas. It happens to me once in a blue moon. My fuel economy just goes to hell.

[PCBeach]

std tires at 35# with mobile 1 synthetic gets me 20.3 hwy, 15.5-16 city. I'm on the flat and drive slow!!