[ToyotaKiller]

I'm no grease monkey however a CAI should increase MPG due to the enhanced performance of the engine. A CAI pushes "colder" air into the engine with contains more oxygen, this allows for greater compression. You aren't going to be injecting more fuel just more oxygen (not more air in general) because we all know that hot air rises thus with colder air you'll get greater compression of fuel to air. Don't look for any miracles, only slight improvements because as you increase the performance of the engine, you are increasing the HP which means the engine doesn't have to work as hard to accomplish the same effect.