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02'-06' Avalanche Owners....How's YOUR Gas Mileage?

I actually had a tank hit 16.5 mpg on our camping trip to Algonquin Provincial Park in Canada last week.  We had the Snugtop on and loaded to the gills.  65/70 seems to be the sweet spot.
 
I've only had my Av for 2 months. I drive about 90 miles a dayjust going to work and back. The first few tank fulls I stayed at about 70mph and got right around 17.5mpg. This week traffic was moving 80 or so and I decided to say the hell with mpg and tag along. Seems I jumped up to 19mpg at this speed. My vehicle doesn't seem to have to accelerate as much going up hill and also doesn't downshift going up the grade. Also, so far my DIC has been off by 1.3mpg(showing low) on every tank.
 
Really happy with my mileage today. I drove from Wisconsin to Arkansas averaging about 80 mph. I got 21.36mpg! I cleaned the MAF and put Seafoam in the oil and gas. Changed the oil and took off. Man I love this truck! Oh, the DIC is still off by .8 today.
 
Backwoodstracker said:
Really happy with my mileage today. I drove from Wisconsin to Arkansas averaging about 80 mph. I got 21.36mpg! I cleaned the MAF and put Seafoam in the oil and gas. Changed the oil and took off. Man I love this truck! Oh, the DIC is still off by .8 today.
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WHOA  :eek: :eek: :eek:
 
I've got bigger and heavier rims combined with wider tires. I guess I can't hope for much more than 15 miles to a gallon with that combination. I'm not complaining though. My truck seems to have celebrity status here. Folks stopping to take pics and commenting as I pull up to a stop light or so so I'll take the lose with a smile.
 
Dluvr22 said:
I've got bigger and heavier rims combined with wider tires. I guess I can't hope for much more than 15 miles to a gallon with that combination. I'm not complaining though. My truck seems to have celebrity status here. Folks stopping to take pics and commenting as I pull up to a stop light or so so I'll take the lose with a smile.
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  :laugh: I love when I look over at the car next to me and get a thumbs up
 
My sons 02 z66 was getting 14-14.8 after complete tune up. Changed exhaust to flowmaster. Milage did not change. Added a cai and Diablosport.  Now get 16.8-17.5
 
Bought the av (2003 5.3 z71)and then drove it home 760 miles in auto 4wd (it's stuck there) a/c, had the cruise set a tad above 75 but there was times I took it past 80-85mph. Hand calculated looks like 17.4 mpg, oh and the front tires are pretty bad, getting all 4 replaced tomorrow.

I suppose I'm pretty happy with the mpg's considering it wasn't in 2wd and crap tires.

The wife's car got 40mpg like it always does..
 
Little update. Put 27 gallons in today, tank was a combination of highway and in town driving, lots of start and stops also still locked into auto 4wd until Tuesday when my part comes in. Anyways, I got 17 mpg for this last tank.
 
My 2003 averages about 11.5 all the time. it is a 2500 4X4 with 4.10's.  The most interesting aspect is that I get the same mileage towing  4,000-5,000 pounds.  To really see an effect on the fuel mileage I have to be pulling over 6,000.  Most ever towed was about 12,500 and it averaged 8.  Remarkable how well it pulled that load. 
 
OmenSpeed said:
Bought the av (2003 5.3 z71)and then drove it home 760 miles in auto 4wd (it's stuck there) a/c, had the cruise set a tad above 75 but there was times I took it past 80-85mph. Hand calculated looks like 17.4 mpg, oh and the front tires are pretty bad, getting all 4 replaced tomorrow.

I suppose I'm pretty happy with the mpg's considering it wasn't in 2wd and crap tires.
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OmenSpeed said:
Little update. Put 27 gallons in today, tank was a combination of highway and in town driving, lots of start and stops also still locked into auto 4wd until Tuesday when my part comes in. Anyways, I got 17 mpg for this last tank.
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My latest tank plummeted to 12.5 mpg in town only driving. Several differences from the previous tanks were, fixed the 4wd selector so I was in 2wd the entire tank. Put on some stock sized e rated tires (heavy) and raised the front end nearly level with the rear end.

I feel the leveling might have some effect on the mileage, maybe I need to clean the maf at this point.
 
My 2005 1500 is reporting 15.1 overall.  I usually drive short distances, but occasionally trips from Virginia to Indiana and back.
 
I just got my 2004 Avalanche (55K miles on it).  Filled it up for the 3rd time last night.  On the first tank, I was excite about my new (to me) truck and was a bit heavy footed with the gas pedal.  Got an average of 13 mpg.  On the second tank, it included driving to and from work and taking the kid to school in the morning.  Lots of stop and go traffic, but I was deliberately trying to be easy on the gas.  Got an average of 11.5 mpg, and that was after cleaning the MAF sensor.

I've decided to just enjoy the truck.  If gas mileage gets to be an issue, I'll just sell it. I got it at such a good price that trading up shouldn't be a problem.
 
Do you have a check engine light on?  A bad knock sensor will cause that kind of gas mileage. Then hand calculate you MPG, the computers are known to be little bit off.
 
I don't have a check engine light on and my calculations were by hand.  Just finishing up another tank.  So far it's looking like 11 or 12 mpg.  Maybe the truck sat too long without being used.  Perhaps pulling the intake off of the throttle body and cleaning it out might help.
 
Before I go shooting in the dark, I think I'll go with the most obvious and change the plugs.  Taking a closer look under the hood, I don't think they've been changed since new.  I only have 57K miles on it, but the idle isn't as smooth and I think it should be.  Probably do the wires too.
 
I just did a 2200 mile trip from Fresno, Ca to Pocatello to Evanston and back. Speeds vary from 65-90 depending on where I was at. I did hit 100 a couple times. When all said and done my BullyDog says 18mpg average. My RPM,s at 80 was 2150. Oil pressure 60Lbs, temp 194.
I was carrying 5 adults and the bed was loaded with gear. And I have 222000 miles on her now.
I did read something interesting, the left valve cover has a baffle that allows the oil blow by to get to the PVC valve. This baffle gets clogged which causes oil consumption and can make your AV have blue smoke at startup for only a few seconds. This usually happens when you work your engine, like climbing steep grades at high RPM's. You get to where you are going, shut off the engine for 5 minutes or 5days. You start the AV and it blows smoke. Mine has been doing this for 100000 miles now. I learned this on Jasper engines website.
 
Wow Shanes.  You're only turning 2150 rpm's at 80?  I'm turning 2200 at 70.  I'm gonna try to get to changing my plugs this weekend and look into the O2 sensors.  They're cheap anyway.  I'm almost to the point to just not worrying about it.  I just drove today and enjoyed my Avy a lot more than I have been.  If the gas gets to be an issue, I'll start looking for something that weighs a ton less.
 
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