[neile300c]

Anyone knows what causes the EPA Hwy ratings to be different on the sedans? When I purchased my 16, it showed a hwy rating of 42. But there were also several sedans that showed a rating of 40 on the hwy. When I asked the salesperson why the difference, he didn't know. Did they 17's go down 2 mpg? I noticed online that every 16 that are around here left have a highway rating of 42. Was Chevrolet "overinflating" the highway mpg?

 

[Chris Tobin]

Probably a refinement in the test procedure/estimate by the EPA... My best guess.

 

[MP81]

The EPA changed their testing procedure, resulting in (mostly) drops across the board at all manufacturers.

 

[pontiacgt]

Depends also on the model. The premier with RS package is 40 and I believe the base all the way to the LT is 42. Premier with the RS package has different tires and more weight. I have a 2016 Premier with the RS and might highest mileage is 41, averaging 34.

 

[obermd]

My 2012 ECO MT also saw the "official" rating drop from 42 to 40 MPG highway. Seems to me like the EPA is generally tightening up on the ratings.

 

[MP81]

My 2012 ECO MT also saw the "official" rating drop from 42 to 40 MPG highway. Seems to me like the EPA is generally tightening up on the ratings.

They're trying to make it more relevant to what is seen in "real-world" driving. And some of the small-displacement turbocharged engines have a bad habit of overstating what they're capable of (*cough* ECOBOOST *cough*). The 1.4T didn't seem to fail to deliver when we took the '14 2LT to NC and back - especially for how much **** we had in the car.

An anomaly seems to be the Malibu Hybrid which actually saw it's city rating increase for 2017 (and its highway rating went down, which is par for the course).