First post! Well i have a 2000 gt coupe N/A. Got a k&n cai off ebay for $100 bucks brand new so im like sure why not. With the stock air box my car was reading 20-21 mpg in the city. After the install its reading 18 mpg in the city now. Pretty sure a cold air should help with mpg so why do you guys think my car is reading the mpg wrong?