Installed a flowmaster cat back system last week on my 04 qc and my around town mileage jumped from 11.8 mpg to avg 13.5. Not bad. I am hoping a cai will help a little more and i will be happy.

 

Nice, anyway you can post pics or get a sound clip. I would love to eventually get clips of each engine with catback exhaust. I posted a Hemi exhaust on the sights and sounds section.

 

Are you serious, that's bad gas milage, I get 16-17mpg depending on how I drive it. 15.7 mpg was the worst that I ever got.

 

Well i live just outside of philly and its alot of stop and go traffic. Also i have less than 1000 miles on it and hope it will improve anyway. Also they oxygenate the gas around here thru the end of feb and that usually drops the mileage as well.