MPG issues
Senior Member
Joined: Nov 2007
Posts: 312
From:
RE: MPG issues
ORIGINAL: alphadogg
Not trying to hyjack this thread but how does one "reprogram the TCM" to help compensatate for the larger tires? I changed my tire size to 33" tires when the truck was brand new so I have no idea of what my real MPG should be.
ORIGINAL: TheGunnyRet
Did you reprogram the TCM to the new size tires. I notice this with allot of people who get new tires and up the size never mention about reprograming your vehicle pcm's which will reduce mpg severely because everything is thrown off. JMO
Did you reprogram the TCM to the new size tires. I notice this with allot of people who get new tires and up the size never mention about reprograming your vehicle pcm's which will reduce mpg severely because everything is thrown off. JMO
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Member
Joined: Dec 2007
Posts: 98
From:
RE: MPG issues
ORIGINAL: importkiller
tony I have gotten 9-10 mpg from day one....35's will effect your gas mileage by 3 mpg MAX...anyone that says it's more hasn't recalibrated the odometer and may think they are getting like 8 mpg less when really it's in the 2-3 range. Or they are going from tiny tires to a 35, not from 32's or even 33's like the adventure to a 35...one full size up will not effect it that much. I've been building lifted trucks my whole life and have dealt with this issue alot. You have an 06, does your vin fall in the range of the bad batch of heads? Mine does and that is what I feel the problem is, but the dealerships have no clue how to diagnose ANYTHING that doesn't come up on a dumb scan tool so.... I only got 11-12 mpg with the base 32's on the truck, so my mileage always sucked.
tony I have gotten 9-10 mpg from day one....35's will effect your gas mileage by 3 mpg MAX...anyone that says it's more hasn't recalibrated the odometer and may think they are getting like 8 mpg less when really it's in the 2-3 range. Or they are going from tiny tires to a 35, not from 32's or even 33's like the adventure to a 35...one full size up will not effect it that much. I've been building lifted trucks my whole life and have dealt with this issue alot. You have an 06, does your vin fall in the range of the bad batch of heads? Mine does and that is what I feel the problem is, but the dealerships have no clue how to diagnose ANYTHING that doesn't come up on a dumb scan tool so.... I only got 11-12 mpg with the base 32's on the truck, so my mileage always sucked.
Joined: Apr 2006
Posts: 7,253
From:
RE: MPG issues
one of the first symptoms of a bad head is rough idle and **** poor gas mileage. Also may get flashing messages across your DIC..I got all 3 but my dealers till said they couldn't replace teh head until it basically left me stranded.
Senior Member
Joined: Jan 2008
Posts: 827
From:
RE: MPG issues
Tony,
That is what happened to my I5 that I had for about 3-4 weeks....it got good mileage at first and then dropped down to 10-12mpg...and I also noticed that it would idle a little rough every once in a while.....nothing major or really noticeable..... The I5 was an 08' model.....go figure....
I would say it might have that head issue......I've been told that even the 08's have been found with the same problem.....I would be heading to your dealership...
That is what happened to my I5 that I had for about 3-4 weeks....it got good mileage at first and then dropped down to 10-12mpg...and I also noticed that it would idle a little rough every once in a while.....nothing major or really noticeable..... The I5 was an 08' model.....go figure....
I would say it might have that head issue......I've been told that even the 08's have been found with the same problem.....I would be heading to your dealership...
Joined: Jan 2008
Posts: 29
From:
RE: MPG issues
I just got my fifth mpg average with my basically stock setup. The average has been about 15.2 mpg (barring the highest tank), and I drive the 405 in mostly stop and go traffic everyday. One tank did get 17, no idea what I did to deserve that though.
Hope you find the problem.
Hope you find the problem.
Member
Joined: Nov 2008
Posts: 65
From:
RE: MPG issues
Giving life to this old thread.... I'm getting Horrible gas milage on my h3, granted.. I didnt buy my hummer because of its mpg performance. Regardless... I'm getting on average 10mpg!!!! In the above post someone mentioned a fan clutch... where is this located and how can I tell if its bad. I just cant figure out why my mpg is so low!!![&o]
Senior Member
Joined: May 2007
Posts: 1,473
From: Central Ohio
RE: MPG issues
ORIGINAL: Supertramp
Giving life to this old thread.... I'm getting Horrible gas milage on my h3, granted.. I didnt buy my hummer because of its mpg performance. Regardless... I'm getting on average 10mpg!!!! In the above post someone mentioned a fan clutch... where is this located and how can I tell if its bad. I just cant figure out why my mpg is so low!!![&o]
Giving life to this old thread.... I'm getting Horrible gas milage on my h3, granted.. I didnt buy my hummer because of its mpg performance. Regardless... I'm getting on average 10mpg!!!! In the above post someone mentioned a fan clutch... where is this located and how can I tell if its bad. I just cant figure out why my mpg is so low!!![&o]
Member
Joined: Nov 2008
Posts: 65
From:
RE: MPG issues
Thanks D Vader! I just dont get why my h3 is getting such horrible gas milage... I guess my only option is to take into the dealer... but even then.. are they gona laugh me away? I mean after all it is a hummer. Anyone else experiencing 10mpg or less in their h3?
