Find an ELF activist meeting, park the H2, put a can of gas and some matches beside it, and let them take care of the rest.
Oh and omgwtfbyobbq, I hate the raised trucks as much as the H2's, but the H2 is more of a symbol because they are more prevalent, on every billboard, and happen to come in their sorry state fresh from the factory. I can understand some people who have raised trucks. I have a friend with one who does alot of mudding in it, but when he isn't mudding, he's driving a Corolla.
I say first thing is to figure out what your current actual mpg range is. If you have already been keeping track of it then you are already doing good. Also fill out the garage info on here so everyone can see your progress and other H2 owners can benefit from your learning what to do.
Assuming it is an Auto trans. The first thing you should do that will help is to try and keep the torque converter locked up as much as possible. The converter probably locks up at 45mph when in OD/4th gear. So if you have a choice in going 40 or 45 I would say go 45. Any time the converter is unlocked you are using a lot more gas than you should. If you are driving in traffic between 35 and 45mph pull it down to 3rd gear. 3rd will lock up at 35mph. But if you go over 45 for more than a few seconds go ahead and go back up into 4th. Also any time you hit the brakes it unlocks so avoid using them as much as possible.
Once the converter locks at 45mph in 4th you can go down to 40mph without it unlocking. 30mph in 3rd. Just think of it as any time the converter is unlocked you are turning some of your gas into heat being generated by the torque converter from slipping and that heat is dumped out the radiator so it is totally being wasted.
I have a friend with a Sierra with a 6.0L engine that got 13-14mpg normal and after she started paying attention to the converter and tries to keep it locked up as much as possible when driving now gets 18mpg with no other changes to her driving style. I keep meaning to run a wire to a small light and hook it to the lockup wire on the trans so it will light up when it locks. That way she can tell when it is locked easier, because sometimes it is hard to tell.
As far as everyone saying sell it or destroy it I say have fun with it and drive it. I have several cars that have worse mileage than you are getting now and also have no emission controls on them but I have no intention of selling any of them
I haven't read eyery post here, but wanted to add that I think Hummer owners take a bad rap.
I live in Texas, where every third or so vehicle is a truck - and not just a regular truck, but a Dodge Doulie 4WD ( that gets 12 MPG tops ! )
I assume the reason Hummers have this bad image is that they are an icon which represents greed.
As far as the mods that you could make to your H2 right now, you could remove the roof rack and block off the grill ( free MPG all you need is a wrench and some coroplast for the grill -you could even put it behind the grill so it doesn't cover up your front end and look funny ! ) ( These could add 2 mpg ..or more )
You can also lower the vehicle and add a flat underbelly.
You could pick up around 3mpg ...and it will lower the center of gravity on the thing which will make a rollover less likely ( it will handle better )
And it will look pimpin too
The above aero changes would mostly work when at highway speeds.
Around town, you'll want to lighten that monster as much as possible.
Leave the spare tire and tools at home - when was the last time you had a flat .... really.
You could also have your gears changed to something more highway friendly - that would help a lot I would think.
Slowing down tp granny speed will have the greatest ( positive ) impact on your MPG.
As far as making the H2 more Enviro friendly, there is not much you can do besides an engine swap .... which is something you might actually really like.
MTV's "Pimp My Ride" recently had '65 Impalla that had a Duramax ( Diesel ) V8 transplant. The motor pumped out over 800 H.P. if I remember correctly ( it blew away a Lamo in the 1/4 th ) ......yet it was powered by clean burning vegetable oil ( BioDiesel ) ....................and the best part ........it got over 20 MPG ! This is in a car that probably weighed in at close to what you are driving now.
An engine swap would be pretty easy with your set up too, since you already have a monster size engine bay for it. You could even sell the current motor to pay for the transplant.
Bio diesel is clean, domestic ... and it smells like french fries too ( Hey that's a good thing Who actually like the smell of regular Diesel ?? )
You don't have to worry that you will be stranded if no bio is available - you can fill up with regular diesel just as easy.
Clean power, doubling your gas mileage, having power out the wazoo ... it's a win / win situation ... and you get to keep the toy !
Good luck !
Edit : One more thing : UC Davis has a suburban that is the one that the Hummer is built on - so basically the same vehicle.
It gets 25 MPG.
How ? The students converted it to a hybrid http://www.team-fate.net/sequoia.html
It now has a 70 mile all electric range, 0-60 speed of 9.3 seconds and a top speed of 99 Mph
The ELF are the Earth Liberation Front. They do all sorts of good things like burning down SUV dealerships, destroying bulldozers, and breaking the engines of logging trucks. They make us EF!ers look like pansies.
for my job we have a work truck that only gets 19mpg empty, and around 12mpg towing 6,000 pounds (trailer loaded with granet counter top), but that is a work truck, same with other full sized trucks, that is why they are alowed to get worse mileage, and are alowed to have varried hight bumpers, because if I put 1,000 pounds of stuff in the back of a truck the bumper is going to get lower, if it's a flat bed, or a tow truck, or has tool boxes then bumpers become even harder to install, a hummer on the other hand... what kind of work is it designed to do?
it's abuseing the system.
Why do you want to save gas, while owning this vehicle? don't you feel justified in burning up as much gas as you feel like? when you bought it the stucker on the window clearly told you what you could expect, I'm sure everyone you know asked you the same thing when you showed up with it tho.
so get better tires, that is going to do the most, from reviews I've read that vehicle can't handle going off road, so it doesn't need off road tires, do some searching on tirerack.com or a simaler site, and find out what narrower road tires will fit those rims and get them, and then keep them at the max side wall presure.
get a scan gauge and install it, think if it as an investment as you can move it from vehicle to vehicle, it will also help you to truble shoot anything that goes wrong, so you can tell how honest a mecanic is.
synthetic fluids will help, they are not a scam.
drive slower, and keep a bike in the back, so when you make a shoping trip you can pull the bike out and ride around to other places you need to go, insted of starting up your vehicle and driving there, it will make you feel better, and make us all breath a little better.
"Some"- you mean, about 98% of the motoring public. This is a big part of why we have an energy/infrastructure pickle. What is there to respect about that?
Well I must be the 2% then. I don't particularly like my car. I'd much rather have a Miata, Fiero, Mustang, Tiburon, Celica, Solstice, etc. than my boring, slow Geo. The only reason I bought it was to save money on gas and it isn't depreciating much these days.
I guess I respect people's choices in vehicles because I pretty much envy any car other than mine. Unless someone else buys a car new, I can't buy it used 10 years later .
I'll never understand the people who work 80 hours a week to buy more shiny new things. I feel sorry for them because their life must be very empty for them to need to fill it with an obscene amount of work and material goods.