2007 Suburban LTZ Gas Mileage

tiffany123 · #1 10-13-2009, 01:39 PM

I just bought a 2007 Suburban LTZ with the 5.3L Flex Fuel engine.
It has 20" tires. I am only getting 15 mpg on the highway and 13 mpg
around town. I know the mpg is not great on these big trucks but
that seems a little low. Is there any adjustments or after market
things I can buy or use to help out with the mpg a little?
Thanks in advance.
LK

777stickman · #2 10-13-2009, 03:14 PM

With the tire change the 1st thing is to check the accuracy of your odometer/speedometer. If it's running slow you're registering less miles than actual.

tiffany123 · #3 10-14-2009, 11:31 AM

I've checked the odometer/speedometer against my other car.
They are pretty accurate. Any other ideas?
Thanks
LK

slyder_ · #4 10-24-2009, 12:23 AM

Quote:

Originally Posted by tiffany123

I just bought a 2007 Suburban LTZ with the 5.3L Flex Fuel engine.
It has 20" tires. I am only getting 15 mpg on the highway and 13 mpg
around town. I know the mpg is not great on these big trucks but
that seems a little low. Is there any adjustments or after market
things I can buy or use to help out with the mpg a little?
Thanks in advance.
LK

Sounds like we have the same truck, 20's were stock on this truck. I just got mine and have the same issue. I get 13 in the city. I can live with it but it does seem low.
Flex fuel was even worse high 11's to low 12's

I'm gonna check the plugs and change all the wet fluids since I'm now the 2nd owner and this will give me a base line.

-Slyder

OSUCowboy27 · #5 10-30-2009, 08:05 PM

Other than making sure that all is normal with your engine and filters, you might try a Hypertech Max Energy ECON # 33000 programmer. It is supposed to get you 2-4 more mpg and more power. Some even report up to 6 mpg increase. I am going to order one but haven't yet. Here is the cheapest one that I have found. Link

When I get one, I will report back with the results.

Siouxicide · #6 11-01-2009, 09:09 AM

I have an '07 3LT with the 5.3 and was getting similar mileage. Recently my transfer case crapped out. They replaced it under warranty and suddenly I was getting 2mpg better all around. So the numbers you're seeing now is what I get with E85. I get 17(H) and 15(C) with regular. Still not the advertised mpg for this rig, but it seems that the transfer case was causing some undue friction and apparently bad transfer cases are notorious for these rigs. Mine gave no warning that it was getting bad.

tiffany123 · #7 11-11-2009, 09:29 PM

OSUCowboy27, I am interested to see if anything changed after you got the
ECON programmer.
I've also found that the mileage is better when I use gas from out in the country instead of
around St. Louis where they have a billion additives in the gas.
Thanks every one for the feedback.
LK

OSUCowboy27 · #8 11-12-2009, 07:39 AM

I haven't yet received the programmer but it is on order.

sub006 · #9 11-26-2009, 04:27 PM

Quote:

Originally Posted by OSUCowboy27

Other than making sure that all is normal with your engine and filters, you might try a Hypertech Max Energy ECON # 33000 programmer. It is supposed to get you 2-4 more mpg and more power. Some even report up to 6 mpg increase. I am going to order one but haven't yet. Here is the cheapest one that I have found. Link

When I get one, I will report back with the results.

Let us know! I have a feeling that if it's that easy and it works, GM would have already make this program standard factory equipment. Maybe it messes up emissions?

POST REPLY TO THIS THREAD