True Delta does not take complaints, per say, but deals with reports of repair frequency to extrapolate reliability statistics. If you end up having something fixed to correct the bad gas mileage, then you can report the repair and they will add it to the database.nyminute said:Signed up own a 2015 GMC Terrain SLE Saphire Metallic Blue
Now what? Wanted to complain about gas mileage . How?
Hopefully you can get it solved. Our Equinox gets great mileage, when driven carefully (me driving) vs my wife!