H3 gas mileage SUCKS

[oneworld]

alomost 2000 miles and the truck is averaging about 15 > 17 > most of my driving is 70 to 80 on the highway and around town softer not working the brakes hard at every stop >so I guess I am not pushing the gas around town. It takes a bit to stop the momentum of the wieght on the H3 so my local driving is low key not ziping around town.

[sharkman]

I appreciate the input. I have put almost 4000 miles on the truck since the modifications.

[f5fstop]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by sharkman:
I appreciate your candidness. The reason I am complaining is that the new TrailBlazer SS has a 395HP LS2 engine (the same as the new Corvette). The Blazer weighs the same as the H3 AND it is rated with the same gas mileage (16/19). I asked HUMMER and Chevrolet how this can be possible: how 2 similar weighing vehicles (outside of aerodynamics) can have 2 totally different engines (a V8 vs an inline 5) and get the same gas milegae! Hell, if I know about the SS, I may have purchased it over the H3 (you get power AND great gas mileage). The answer given to me was, "I know it is frustrating, but I don't know how to explain it." </div></BLOCKQUOTE>

it takes less throttle input to move a vehicle with a large V8 with torque to spare, versus a five cylinder that does not have torque to spare. Yes, a V8 with less throttle input is using more fuel than the five cylinder using the same throttle input, but the five cylinder would require a great throttle opening. This would only affect starts from a stop, unless you were passing.
Also, even though the trailblazer is not considered aerodynamic, it is extremely aerodynamic when compared to the Hummer H3, which is similar to moving a wall down the road.
I'm also guessing, but I would guess the trailblazer weighs in at about 500 pounds or less than the H3. The H3 has a heavier frame, extra cross members, and heavier front/rear axles and transfer case.
As I have said earlier, the fuel mileage figures given are based upon a Fed Regulation on how to determine fuel mileage. These tests are performed under ideal condition, and really do not reflect actual driving done by you or me.
It does sound like you not getting as good of mileage as others, but it could be due to your driving habits versus others, the wind, the altitude, etc.
I know from what I have seen so far with my mileage, I have no complaints.

[sharkman]

I am trying to find out what the average MPG you are receiving on your H3. I have 5500 miles on the truck and have received AN AVERAGE of 14-15 mpg driving on the freeway. I have taken the truck to (2) dealers and neither can find anything wrong with the vehicle. As they say, "the vehicle is performing within specified parameters." Is anybody else experienceing the crappy gas mileage?

[killian]

I'm not real sure that I care what kind of mileage I'm getting, I just enjoy driving my truck.

[bparker]

Have you checked to see if you have any Hondas or Toyotas stuck under your bumpers? You might have one adding weight to your vehice thus poorer milage. /shrug

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by sharkman:
Thanks for the input. I am going to drive 2 full tanks @ no faster than 70mph highway and see what happens to my mileage. </div></BLOCKQUOTE>

[trading13]

LOL thats cute. I hope a saint bernard fits ok in an h3.

[sharkman]

what mpg did you get on this trip, average?

[sharkman]

My foot isn't heavy at all. I do tend to drive 75-80 on the freeway (which is what Hummer says is the problem). I traded in my YUKON XL for this truck and I haven't changed my driving habits at all. Ironically, the Yukon, with a 5.2L V8 got better gas mileage than this H3, with the 3.5L inline 5. I definitely don't accelerate at a light or stop signs. My H3 is an automatic.

[sharkman]

Good question. I drive about 75-80mph, give or take with the AC off. HUMMER claims I am driving too fast and this vehicle isn't meant for those kinds of speeds. How fast do you drive, typically?

I don't accelerate abruptly, either.

[HummerNewbie]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by f5fstop:
but I am well known for jack rabbit starts, </div></BLOCKQUOTE>

My dog thinks I do that as well

[Desert Dan]

for a 4700 pound brick shaped SUV I think the mileage people are reporting is pretty good!!!

I wish my Jeep did as well.

GM didn't claim 19-20 mpg in the city!

[DWPC]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">How 2 similar weighing vehicles (outside of aerodynamics) can have 2 totally different engines (a V8 vs an inline 5) and get the same gas milegae! </div></BLOCKQUOTE>

It IS the aerodynamics! Drag goes up with a cube factor. The H3 is a box (actually a bunch of boxes stuck together). Compared to the H3, the TB is downright streamlined. Going from 70 to 80 increases your H3's already high drag dramatically.

[wannabeH3]

i really enjoy the H3 but i fully agree the mileage is pathetic and no where near the advertised 20 mpg i typically get between 13-15 mpg

[bparker]

Yes, those are the short term fuel trims and they are changed for driving conditions - but they will not be correct until the long term fuel trim tables are updated after 500 miles - then and only then will the short term fuel trim tables be accurate and optimized.

Brent

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by f5fstop:
Air/fuel misture on the modern engines is almost instantaneous. The PCM constantly reads the O2 sensors, as well as the MAF sensor, air temp sensor, ect., it then computes the most optimum air/fuel ratio, and constantly changes this as you drive. Chaning the air filter or cat back exhaust will be sensed almost instantly by the computer. Besides, there is litte to no affect with these items in regard to air/fuel mixture.
The transmission has a learning capability, called adaptive strategy, that will adjust with driving over a period of time, usually within 50 miles. </div></BLOCKQUOTE>