I own a 2004 Mach 1 that has a check engine light on constantly. I had Ford replace the computer module in it that was reading a Mazda 1.3L turbo diesel. Ford stated that it had failing o2 sensors, so I replaced all 4 with new Bosche (sp?) o2 sensors. It is still throwing a code so I scanned it and so far I have one code being thrown but it had two different readings. One said o2 sensor slow response driver's side, and the other said System Running Lean (Left Bank). Any ideas on what might be throwing codes?