3-4 MPG drop on 09 Yukon Denali

[Hopdaddy]

All-

I am experiencing a 3-4 miles per gallon drop in the city and on the highway respectfully on my 2009 Yukon Denali with 55,000 miles. Problem is no codes are pulling up. Any thoughts? Regular maintenance is done on the vehicle and tire pressure has remained consistent.

Thanks

 

[tahoebigah]

heavier foot or bad gas?

 

[JennaBear]

What octane are you running? Clean your MAF and throttle body.

 

[YukonCrazy]

Is there a tutorial somewhere on how to clean the MAF and TB?

 

[JennaBear]

Wouldn't be surprised if there was on you tube. Otherwise, it tells you how on the back of the cans.

Sent from a jelly bean.

 

[Hopdaddy]

Have run all 3 grades thru. Tried a couple of tank fulls at 93, but no change. Will try and clean TB and MAF.

It's babied around town and 70-75 on highway.

Thanks

 

[jdpber]

Willing bet TB needs clean and new intake filter. You would be surprised how much a dirty TB will offset performance reading to the motor. I clean mine every oil change.

 

[Parthery]

It may also be summer gas.

Depending on where you are, the oil companies change the formulation of gasoline for summer months in an attempt to keep down smog....the "summer gas" formulation is not as efficient.