Low MPG's

[Sesco4]

Maybe I'm wrong but it seems like my gas mileage is getting worse. I have a 07 Yukon with a Black Bear Tune Airaid Jr. intake and Magnaflow muffler. The Black Bear tune has disabled the active fuel management and stays in V8 mode. My mileage around town is under 13 and highway is around 16. Does this sound right or is it low. If it is low how can I get it back up. I'm seriously considering putting my factory tune back in.

 

[JennaBear]

Clean your throttle body and your MAF. Also, what gas are you using? AutoCal tune?

Sent from my fone.

 

[Sesco4]

I'm running Shell gasoline with the 91 octane performance tune.

 

[TheAutumnWind]

Better than my 6.0 Yukon XL Denali!

 

[JennaBear]

If you have an AutoCal, shoot a data log over to the guys for them to analyze. Could be bad gas.

Sent from my fone.

 

[Sesco4]

I got the MAS and the Throttle Body cleaned. The TB was pretty dirty. I'm going on vacation tomorrow with a 350 mile one way drive. I will see how it does and try to get a data log when I get back. Thanks

 

[ccapehartusarmyINF.(ret)]

make sure yer tires are all inflated to the recomended pressure

 

[Sesco4]

Tires are Nitrogen filled at the proper PSI.

 

[ezdaar]

you should log it during the trip.

 

[Sesco4]

yeah I'm going to keep track of the gas mileage and hand calculate. The same trip one years ago I got 19 MPG two months ago I got 16 so something is off just don't know what.

 

[ccapehartusarmyINF.(ret)]

Tires are Nitrogen filled at the proper PSI.

are they still peddling that nitrogen deal that cracks me up
so now were putting 93 percent nitrogen in our tires instead of 80 percent

 

[Sesco4]

I filled up before leaving Virginia on my way to South Carolina. The trip was 353 miles. I filled up this morning with 22 gallons. Hand calculated is 16 mpg. The computer is showing 16.5 so roughly the same. I have 140 some thousand miles on the Yukon now so could it be in need of a tune up. Thanks

 

[Badmunky]

I have the same problem.
Less then 13mpg around town, and around 16mpg highway.
I cleaned the throttle body, map sensor, maf sensor, new plugs, new wires, new O2 sensors, ran some seafoam threw it, then paid to have the injection system cleaned as the seafoam didn't help. No change.

I gave up and just deal with the crap MPG.