gm says that they cant check it when the weather is cold im supposed to check it again in may

GM vehicles always get poor MPG- they are also pretty poor in dependability. l know a guy who just got a 08' Silverado- has 18k miles and needs a new transmission

try to keep your foot off the gas pedal. some cars are just meant to have crappy fuel milige.

What l would have them check is the alignment of the truck first because l see alot of vehicles that r out of specs & many vehicles from the factory r out of specs & as for the comment above, GM trucks get the best gas mileage of all 1/2 ton trucks around...........

Ford F-150

4.2-liter V-6: 16/21
4.6-liter V-8: 15/20
5.4-liter V-8: 15/19


Chevrolet Silverado

4.3-liter V-6: 17/21
4.8-liter V-8: 16/20
5.3-liter V-8: 16/22


Dodge Ram

3.7-liter V-6: 16/21
4.7-liter V-8: 14/19
5.7-liter V-8: 15/19


Nissan Titan

5.6-liter V-8: 14/18

Toyota Tundra

4.0-liter V-6: 17/20
4.7-liter V-8: 15/18
5.7-liter V-8: 16/20

l do alot of city driving and my truck gets 14 or less. However, on a 300 mile trip recently, it got 21 mpg.

Actually have a 07 Sierra w/5.3 active fuel management 4x4 1500 auto xcab the following r mileages we got on a trip,w/ ac 2 average adults &luggage, using cruise 98% of the time. 22.9 68 mainly flat terain,20.1mpg 72 hilly terain,19.2speeds in the75to85 range hilly terain not always using the cruise. Thats with using 87 octane no consistant brand. So the experts who test these vehices r right speeds above 65 do make a considerable difference in fuel economy. u did not mention what engine u have but i've found that engine size rearend ratios make a significant difference The diff. ratio in ours is 3.73.

Fuel Milage Varies considerably on u driveing habits, if u have a heavy foot on the highway u will get worse milage. If u excellerate like ur drag raceing, u will get bad milage. If u break hard u will get bad milage. If ur truck is not set up the way u need it u will get bad milage.

What motor do u have? whats u Rear axle ratio, r u lifted or running stock. To many variables.

l have had some people say they r not getting great milage, but the majority of my clients with the 07/08 MY (model year) sierra is & silverados r very pleased with the milage, & l myself have been impressed as well. And dont go by the on board Average fuel economy in ur drivers information center, unless u reset it everytime u hit the highway because it averages ur speed & and fuel consumption for every mile on ur truck, Your sales consultant should have told u that. Get an old school slide ruler & go by the always dependable fuel in-Milage out formula, l will almost garuntee u will see improvment in numbers.