I notticed that when I took it off this is how my mileage has gone since I removed the CAI and the TB spacer. I drive 60% highway 40% city and fairly agressive. Exhaust, CAI, TB Spacer = 16.6 mpg avg Exhaust, TB Spacer = 15.2 mpg avg Exhaust = 14.3 mpg avg (the avg I got on the last tank of gas, 87 ...