The only engine mods I have is a new K&N filter & 3" Magnaflow cat back exhaust. I installed a Innovate wide-band gauge & I can now read real true A/F at WOT. I was surprised to see how lean it is at WOT now. I didn't get a reading before since my wide-band was my last mod. I have ran a wide-band on my last 2 cars & usually factory tunes are always pig rich at WOT. When I say lean I mean 13.8 to 14.2 at WOT. I advise anyone with this mod to enrich fuel in all ranges 2k to red line with your hand held tuner or better yet get a fresh custom tune with them using a wide-band/dyno combo. Simple enough to do yourself if you have a wide-band & a hand-held tuner in the modify tune area. It should run in the 12.7 to 13.1 max range. I know a lot of people now run 3" magnaflow cat backs so I can assume yours is doing what mine is & probable leaner if you have a custom tune. If a factory tune is that lean (usually factory is pig rich) a custom tune will be even leaner. Might just check it out with a wide-band. The only way to know for sure. My wide-band is new & had a fresh air calibration (best type).