Hey everyone. A few questions. About 2 weeks ago I installed a cold air intake on my 2004 SLK 230. Yesterday the check engine light came on after driving about 20 miles. The codes were: P0131 and P0171. Low voltage on the O2 sensor and Bank 1 lean. Could this be because of the CAI? I have not had any programming done. If so, I can go back stock. If not, could it be the O2 sensor going bad? Still learning this car as I have been a Mustang guy all my life. Any help and/or insights would be greatly appreciated. Thanks!