My 2003 still gets 10.4.. Got a heavy foot. didn't care what the mileage was before I bought.. I do not care now after 8K miles.. still get 10.4mpg.. WOuldn't even know this if the H2 didn't keep track.. I just go to station when its thirsty and move on.. Like my daughter says its a "coke machine with wheels, not a sports car"..
ALl I know is its cool and mileage is not a issue in INdy with gas back down to 140 a gallon.. Besides I am use to feeding my older custom suburban that gets under 9 mpg ( I think). and it holds 45 gallons and I have to use prem + booster to feed the supercharger. So the H2 mileage ain't no big thing.

Mike

So I did more experimenting over this weekend. Best I got was 17.6 MPG with cruise control at 55 MPH. No joke. Overall I'm still getting 14 MPG. Mostly suburban driving and with a fairly light foot granted, but still better than I expected.

Mine has dropped another tenth to 11.3, but I do not care. I have a very heavy foot and love the sound.
If I want better mileage I can drive the Tahoe. It gets just over 14 .

Black Lingenfelter Lux

Texas Red...now there's a name I haven't seen for a long spell...how've ya been bud?

I've heard that the 2004 has different engine programming than the 2003?

Any truth to this?

Any official word from GM?

ya, 14 mpg overall? RIGHT. Only if being towed! There is no GM literature stating any changes in MPG, and if there were any change for '04 you can bet your ass that GM would have advertised that up one side and down the other, since mpg is the greatest weakness than the public can come up with for the H2.

gasman

I did expect people to think I was exaggerating. I'm waiting for other '04 owners to chime in.

I just got to drive the wife's 04, w/ 400 miles it seems more responsive than the 03 w/7000 miles.
The wife also made the comment on the way home after trading that she thought it ran better.

The 04 is showing 11.6 mpg and the 03 took months to get to 11.4 mpg.

Yell'r 04 Lux w/ air, sunroof,F&R brush bars
Traded 03 White Lux
03 GMC D/A CC SLT LB soon to be 04

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>if there were any change for '04 you can bet your ass that GM would have advertised that up one side and down the other, since mpg is the greatest weakness than the public can come up with for the H2.
<HR></BLOCKQUOTE>

No, GM can't advertise that. The fuel economy figures are not posted on window stickers, because only the EPA can rate for MPG, and the EPA will not test the H2. So any improvement in MPG has to be determined by the owner. It's just that GM can't say anything positive or negative on MPG since the EPA doesn't test.

I have heard that the Vortec family of engines did receive some airflow modifications to their basic structure, and the engine in the H2 is a Vortec. Not a full generational change in engine technology, but at least an "improvement" I doubt that it's a programming change in the main computor or TCM, but it could be worth looking into your TCM chip for improving performance.

Nobody expects the Spanish Inquisition!!

My average is showing 11.1 mpg. My mileage improved on my '04 with the headers, exhaust and cold air intake. I have yet to install my Xtremeflow software upgrade. Hopefully I will get up to 12 mpg.

04 H2 Engine upgrades by Rod Hall Racing
02 BMW M3 Convertible
95 Ferrari F355
01 Ducati 748

Just to join the opinions I have a 2003, very early production. My average according to the meter is 10.8. This is 50/50 (Highway) and I consider myself to have a LIGHT foot. My calculations are always about 2 mpg higher.
Straight highway I calculated 15.5 at best. I just wonder how accurate theses GM meters are, should we trust them, I would suggest to calculate your own milage.
On another note I am looking into programmers and exhaust systems. Pretty confused on which to go with. Any suggestions? Thanks in advance!

Doug
2003 Metalic Red H2
Adventure Series. w/navigation/Sat Radio/Winch

3500 miles on mine and its dead on 11.1 and that is mostly back roads with lots of hills. Also quite a bit of start and stops. My Silverado averaged about 13-14 on the same roads. The Escalade is 13.6.

03 Sunset H2!
89 Vette
02 Escalade