I have a 2005 v6 Mustang. Only mods are CAI and Exhaust. Anyone have a problem with a P0171 System Too Lean (Bank 1) code? There are so many possibilities that can cause a lean code. Has anyone else had this problem or can anyone lead me in the right direction. I have not found any vacuum leaks and i have also cleaned the MAF sensor. The car only has 56,000 miles on it. Anyone have any ideas?