• If you currently own, previously owned or want to own an Avalanche, we welcome you to become a member today. Membership is FREE, register now!

Increase Gas Mileage

Gitano2004

Full Member
Joined
Dec 14, 2011
Messages
100
I have a 2004 Z71 WBH. I'm just under 50k miles. I"m generally pretty good with regular maintenance (oil changes, air filter, etc...) I have General Tire Grabber AT2 (load range E) that I keep at 50psi...
I don't drive too crazy, I try to not jump on the gas too much, but I'm only averaging about 11mpg!!
Keep in mind that 98% of my driving is everyday stop and go, and I'm in south western PA so there's a ton of hills.
I've only had the truck since July and except for the tires I have not performed any upgrades / mods.

Any good, not too expensive suggestions for increased gas mileage? I know that the 5.3 engine is notorious for being tough on gas, but I feel like I should be getting at least 13-14mpg.

I LOVE my truck, but it's really taking a toll on my wallet, especially since my vehicle prior to this was a 4cyl Honda.

Thanks!!
 
I have a 07 and it was getting 17mpg when I got it.  I put on a cold air intake system and it gave me 2mpg boost. I don't know if it would translate  to yours or not.  Cost average around $300.  Just one place to start.
 
IS that 11 highway or city?

something is wrong for that low...

heck I have been getting 16-17 per tank for over 10 years...

and I cruise interstate more then not as average speed is around 40 mph... per hour meter.
 
I have an '04 WBH too and only got that low during the summer when I had to run the A/C constantly. I average 16-17 mpg.

Coincidentally whenever I use 10% ethanol, which is fairly common in my area, I see mpg drop by a minimum of 1 to almost 2 mpg. Don't know what it is about that gas that my truck doesn't like...
 
'02 Z71 4x4 with all its tupperware glory...I average 16-17 as well...and that's an over all average.  Mostly stop and go short trips.

When I use ethanol, I drop 2-3 mpg and my truck doesn't run near as smoothly.  I pay the extra $0.13/gal for good ole 87 dino gas...well worth it, truck runs better, and I get more miles per gallon.
 
I agree that even with no modifications (cold air intake, etc...) it seems way too low. But when I check the odometer it gives me a reading of about 11mpg and even when I do the math myself it comes out to that.
It being a cold Pittsburgh winter, I of course let her warm up for a little while in the mornings. I know that doesn't help, but there's no way that accounts for the 3-6mpg loss that I seem to have.
I'm almost exclusive city, stop and go driving, but something just doesn't seem right. Luckily winter is almost over so when spring rolls around I'll probably do the cold air intake (and all around tune up) and see what happens. Maybe even an exhaust, I wouldn't mind a little more of a rumble.

I'm a new owner, and despite this mpg problem, I still love my truck! There is no vehicle out there that even comes close to functioning so greatly as both a family and work vehicle.
 
The warmup can knock down the mpg pretty quick. I would try without the warm up for a couple of tanks. No ethanol gas will help even with the tank after if you want to alternate.
 
I too noticed almost 2-3 MPG drop when I remote start to warm up in the morning (usually only 5-7 minutes) but it does make a difference. The truck idles in 8 cyl mode and if it's not moving it will drop your MPG. I agree 11 is an awful number. I did a MAF sensor cleaning, along with a Seafoam treatment (both the intake spray and the liquid. 1/3 dripped into the brake booster line, the rest in the tank, and picked up over 1 mpg... cost around 35 bucks) Also pull a plug and check it for any signs of wear, also ensure you are using the correct type, most guys recommend using the AC Delco Irridium.
 
Thanks for all of the feedback!
Like I said I bought the truck used in July and although the original owner appeared to take good care of it, it seems that he traded it in right before it needed a nice tune up. And wow! I can honestly say that I did realize the warm up would hurt that much. Again, I'm still adjusting going from my 4cyl honda to the 8cyl chevy. I think if I minimize my warm up, change plugs / wires (assuming they need it), etc... I can pick up at least 2mpg, which doesn't seem like much, but for me that's comes out to be almost a weeks worth of driving back and forth from work.
 
I think with stop & go driving with hills you are not going to do much better than you are........I doubt that you need plugs and wires at 50K. If you minimize the warm up time that will help some.
 
Z66 BUTCH said:
I think with stop & go driving with hills you are not going to do much better than you are........I doubt that you need plugs and wires at 50K. If you minimize the warm up time that will help some.

It depends on the hours on the truck too. If there's a lot of idling and stop-and-go on the truck for 50K, it could well need plugs and wires.
 
Joelg1980 said:
I have an '04 WBH too and only got that low during the summer when I had to run the A/C constantly. I average 16-17 mpg.

Coincidentally whenever I use 10% ethanol, which is fairly common in my area, I see mpg drop by a minimum of 1 to almost 2 mpg. Don't know what it is about that gas that my truck doesn't like...

Any vehicle will get worse mileage on Ethanol. It's a characteristic of the fuel.
 
Another thing to consider how long are most of your trips? If most trips are under 3 miles that can cost you 2-3 mpg without warm up time.

Also PA only has 8 gas stations that sell gas without ethanol according to this site http://www.buyrealgas.com/ may not be worth the extra gas to get to 1.
 
That website isn't very reliable. I know of at least 4 stations in my immediate area that sell non-ethanol gas but the website shows the closest station being in Marion.

Wazbro said:
Another thing to consider how long are most of your trips? If most trips are under 3 miles that can cost you 2-3 mpg without warm up time.

Also PA only has 8 gas stations that sell gas without ethanol according to this site http://www.buyrealgas.com/ may not be worth the extra gas to get to 1.
 
11 MPG is way low.

However, a three-to-five minute warmup is a bit excessive. I imagine thirty seconds is enough.


I generally get 15-17 around town while commuting, even with hills.


Couple of observations - you have a 2004, which hasn't been driven much. I mean 50,000 miles on an eight-year-old car? (I have almost 110,000 on my 2006, by comparison.)  You could have some serious build up in the injectors as well as possible other issues that could easily be remedied with a tune-up.

If you REALLY want mileage, however....



 

Attachments

  • milenovic_yugo_03.jpg
    milenovic_yugo_03.jpg
    37.6 KB · Views: 726
i really dont want to sound ignorant , as i too want the best milage out of my avy as well !
but .... your talking about a 5000 - 6500 lb vehicle designed to haul and tow ..............
not designed to get good milage ??  MOST avy's have a lower gear ratio with an average 3.73 to 4.10 not being uncommon
this is for towing and GREATLY affects the vehicles milage !! this is the reason is 2009 the avy gear ratio went to 3.43 being
cosidered a "low " gear ratio and standard (for lack of a better term ) ratio is now 3.08 which is very high for a truck ! even for a
truck with a 6 speed trans ..... with the ultimate goal to meet the government milage and emmision standards :(  !!!
 
Don't get me wrong, I'm not expecting the 25+mpg I was getting with my Honda, I bought the truck knowing that they do not get good gas mileage. It's the fact that everyone else seems to be getting at least 13 and I'm barely getting 11 that I don't like. I'm definitely going to cut way down on the warm up time, and you hit the nail right on the head, a lot of my trips are between 3 and 7 miles.

Yeah the guy clearly didn't drive the truck much, I bought it towards the end of July 2011 with 43k on it (roughly an average of 6k a year). I'm almost at 50k now, so I've put more in 6-7 months than he did in a year (on average).
 
Everyday stop and go with a ton of hills....I stand my my statement that you are not going to do a lot better. There is a differene between city driving and urban driving, add in the hills and you are doomed.


I have a 2007 that has the ability to view instant MPG and driving like you discribe I could not even get 11mpg. However I can get real world 20mpg +- on good smooth interstate driving. I am 5 miles from town, driving back and forth and a little in town driving and I am getting 13-14MPG.  Add in the real city driving with a lot of stop and going + the hills, right back to 10 - 11mpg.
 
Friend of mine in college had one of these. He'd routinely get 50 MPG + driving around town. I was getting barely 18 MPG in my Nissan pickup.

 

Attachments

  • 78vwrabbitdiesel.jpg
    78vwrabbitdiesel.jpg
    37.1 KB · Views: 688
Please read the following thread I posted in. Sandlapper experienced excellent results, as I have with a simple and cheap cleaning of the intake/fuel system.

http://chevyavalanchefanclub.com/cafcna/index.php/topic,131568.0.html

No guarantee you will see the same results, but for the money and time invested I can't think of any other treatment or mod that will give these type of results.
Considering the last owner barely drove the truck, the odds of carbon buildup are very very high. Check other threads on the use of Seafoam as you should follow the directions very carefully!  
I know it's starting to sound like I own stock in this product the way I talk about it but, RESULTS DON'T LIE!!
 
Seafoam rocks!

I did this to my '95 Jimmy back in '99. Works great.  I haven't needed to do it to my AV yet, but I do pour in Lucas every six months or so into the tank.
 
Make y'all feel better either one way or the other  >:D

I have tracked my mpg since I first bought the AV in 2002. Well, I get between 12-14 mpg. That's over 10 years  :cool:

Since I just hit 50K and have a check engine light that has just come on. I'll be making a bunch of changes ie  plugs, wires, etc

Guess I'll see if there will be a diffference  :rolleyes:

-IM
 
USE AC DELCO PLUGS!  I would also try a Hypertech tuner. Try some Chevron Techron fuel injector cleaner.

Avalon
 
                                    I purchased my Av 2/11/12, the mileage average was 15.9 when I test drove it. I live in Pgh also. The flex fuel engine (Z) Code averages 1 mpg less than a gasoline engine. Daily driving with 116,000 mile is 12.9 mpg. Highway is 17 mpg. My only recomendation would be to check the air filter. For a vehicle that weighs 7,000 lbs, it really isn,t that bad. My trailblazer gets 14/19 and weighs 3300 lbs less.
 
Back
Top