so just put on my cai and retuned my 09 with tunes i got from brenspeed along with adding the steeda throttle body spacer and my gas milage has gone down big time and its not from having a heavy foot
yepp got the cai, spacer, and tuner w/ tunes and it drops a **** ton right away when stopped never did that before. i went from 17-19 city now it 15-17
I had my car dyno tuned with my Roush CAI and my gas mileage went up about the amount yours went down. The tuner told me this was typical for this mod.
Make sure you check the Gear Ratio and the Revolutions/Mile that are set-up in the Optional Parameters on the Tuner. For proper revs/mile you can go to your tire manufacturer website and find your tire size and find the proper revs/mile. If your tires/gear ratio are different than what's programmed, this could be giving you incorrect calculations for your gas mileage. Check those items first and if you have no luck, contact Brenspeed and they should be able to help you out, as they have great customer service.
Saw the same thing with Brenspeed. I switched to a VMP tune and my mileage and low-end torque were back.