2011 CTS Sportwagon
My 2011 3.6 CTS Wagon gets the worst gas milage! I love this car! Runs great! My only gripe is the milage. Combined highway and city is 15-16mpg (according to instruments) My wife has a 2019 Camero SS with a 455 in it and it gets 22!!! The only thing added is an aftermarket exhaust (magnaflo) What's the secret to punching up the milage? Any mod suggestions? There's got to e a trick???