Did you get a tune installed for the intake? If not you need one to get the proper performance out of it. Our inTune
has the tunes pre-loaded for Airaid to make sure you are not running too lean and that your vehicle pulls timing because of what it sees for A/F ratio.
If you already have a tuner, was the tune built for the cold air? If you do have a tune for the cold air already, it would be curious to hear that you lost mileage.