Poor Gas Mileage for Tahoe LT 2008

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Ed Alexander

Member
Joined
May 26, 2021
Posts
53
Reaction score
9
Hey all, I bought my 2008 Tahoe LT a year ago however I did not really drive it in the summer as it was off the road. When I put it on the road in September (Living in New York) I was getting average 12-14MPG with 89octane gasoline.. Had the A/C on most of the time as September was hot.
I decided to put in E85 to test it in the past 2 months on and off. Performance I noticed was not that good as it was harder to start my tahoe and gas went down to about 11mpg. I just let the gas run under 1/4 tank and put in 93.

Question I have is should I see a drastic change in MPG immediately or will this take a few more fillups to see results?
I tried almost everything I could to see even idling mpg which when i reset the average mpg on the dash it should 6-8mpg with the ac running.
I tried everything I read on the forums...
I have my tires at 32psi,i run recirculation,changed air filter, changed all spark plugs, i dont have anything in the truck to weigh it down.
 

Foggy

Full Access Member
Joined
Jul 25, 2019
Posts
960
Reaction score
1,153
Location
KS
It will take about 50 miles for the computer to alter the fuel and timing info
between the E-85 crap and real gasoline... Just give it some time.. Remember you
still have 1/4 tank of E in there.. So on the next fill up you should be back to your
normal gas mileage
 

swathdiver

Full Access Member
Joined
May 18, 2017
Posts
19,100
Reaction score
25,031
Location
Treasure Coast, Florida
I decided to put in E85 to test it in the past 2 months on and off. Performance I noticed was not that good

By switching back and forth, you never let the E85 get up to full strength and maximum power. It takes 3-5 tanks to get up to an 80% octane level, if that's what the pumps are delivering.

Your vehicle is rated for 14 city and 20 on the highway burning gasoline. It is rated for 10 city and 15 highway burning full strength E85.

If the price is low enough, you can actually reduce your cost per mile burning E85 or a mix of gas and ethanol.

My truck gets its best mileage burning a mix that delivers an alcohol content of between 16% to 22% or so. This also delivers its lowest cost per mile to drive.

These motors love to burn it, it's like cheap race gas.
 

SUMTOY2

Member
Joined
Apr 25, 2020
Posts
34
Reaction score
10
Driving in the heat with ac on will kill your mpg,especially in stop and go traffic. My 08 gets so so mileage around town. But when I go from Arizona to California I get about 475 miles to the tank.
 
OP
OP
E

Ed Alexander

Member
Joined
May 26, 2021
Posts
53
Reaction score
9
what i am now getting is 13 mpg after figuring everything out. I took out my rear 2 seats, making sure i have 32psi tires, i put in 87 gas from BJ's.
 

Forum statistics

Threads
128,792
Posts
1,805,544
Members
91,777
Latest member
DamThatRiver24
Top