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Decrease In Mpgs

rgibbs11

By rgibbs11
in Ask A GM Technician

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rgibbs11 Enthusiast

rgibbs11

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Posted

I have a 2001 GMC Yukon, 5.3l, with 107K miles on it. It used to get around 17 mpg and the last 3 tanks of gas it's been around 11-12 mpg. I am the original owner of this vehicle and winter blend has never had this effect before. This Yukon had a new fuel filter, air filter, and a tune up about 5K miles ago. Tire pressure is good. No change in driving habits. Still using the same brand of fuel.

 

Any ideas or suggestions?? Thanks in advance.

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