Hope you get it sorted out, mine gets 18.5 avg city driving and thats not always babying it, it was 18.9 this summer.

 

my lumina (rest her soul) was getting around 20 mpg, they are basically the same as the 5th gen monte carlos

 

My monte gets around 20 mpg in the city and 33 on the highway. I don't know how you're getting such low mpg

 

im getting 21.7 according to my heads up display

 

My LS does ~25 city/33 highway. All my maintenance is done regularly though. Full syn oil with UPF52 filter every 3k, trans service every 15k, change power steering fluid every 20k, plugs and wires (ACDelco), 35psi front/32psi rear with quality tires(Pirelli), Tires get balanced and rotated at every oil change.

 

my commute is terrible with stop and go. I still get 19mpg

 

dont feel bad i got 11.1 on my last fillup

stupid 65lb injectors lol

 

Change your pre-cat O2 sensor. They get lazy as they age and also have a lot to do with gas mileage.

My supercharged 2004 gets around 24-25 mpg usually. The best I ever got was 29 mpg on one tank going out to Georgia last year. This was after I had installed the Borla Cat-back. Before that the best I ever got was 27mpg and this was with a full tune-up and O2 sensor replacement.

Wayne

 

is this the 02 sensor you can see from under the hood near the back/bottom of the engine? i heard these cars have more than 1 so id ask and how hard is it to replace one of these babies?

 

idk if its just my monte but my heads up display seems to be wrong about ALOT of the stuff it does according to that i get around 20 mpg too but that is nowhere near close to what i get, i only use it to see how the weather is outside and which direction im facing, that seems to be the only right thing on there.....still nice feature just wish everything was accurate