have an 03 H2, computer was reading 13.0 miles to a gallon, then 12.9, now 3 months later it is to 12.8 miles to a gallon. Any ideas whats going on. Would plugs do this? Also, going to need tires soon. Looking for a quiet tire, no offroading. Anyone have any ideas on this one also? Thanks everyone

 

The mileage always varies...0.2 mpg isn't even worth mentioning. There are so many factors: Tire pressures, outside temperature, winter vs. summer fuel, wind, wet roads, more traffic, varying driving habits, passangers or cargo in Hummer.....I would be concerned if it drops by 2 or 3 mpg, but how can anybody expect the fuel consumption to stay exactly the same..... And anybody buying a H2 will obviously not be concerned that much about fuel consumption

 

rezero out your mpg so you start out at zero and not the average .