My 99 v6 mustang has a weird chugging sound when you have it in gear while breakin. I've scanned it and I got a Lean code on it, it's not saying it's one of the O2 sensors. Eva, cata, air icons are blinking on the scanner. Can some point in the direction to solving this problem? People are telling me it's the fuel filter and others are telling me the engine is leaking water in to the exhaust.