my 2003 aviator i coded it out with a OBD and po171 and po174 came up on 2003 Lincoln Navigator

this is lean cylinders left bank and leaan cylinders right bank. What would cause this?

Asked by for the 2003 Lincoln Navigator
look for vac leak. poss pcv hose is bad and causing leak. fords are good for this. it could also be serveral other items like mass air flow or injectors issue. if you can't find a vac leak have a smoke test done on car and that will show you any leaks. but pull pcv hose and insp that 1st. DO YOU HAVE HIGH IDLE?
no only when it first starts. only issue besides the check engine light on is a slight shake of the engine
i believe you have a vac leak causing the problem ck pcv hose 1st its very common
yes it was a collapsed elbow and there was a hole in it. You were spot on Thank You!
you are so welcome,its people like you that make my time on this site worth it
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