I was getting 28 mpg last winter and spring with a plenum spacer CAI and catback exhuast. But i was shifting at 2000-2500 maybe 3000 if i pushed it. Alot depends on driving habits. One time i had to follow my friends mom to get somwhere cuz i had noo idea where it was and she had the gps OMG she drove the freakin speed limit like 55-57 the whole may i got 33MPG for that trip i was soo pissed off though i hate driving slow.

 

A tune-up?

 

how accurate is the MPG gauge on the car?

 

I did the calculations a few times mathematically and I always got close too or the exact same number as the gauge soo Id say its pretty accurate.