How many o2 sensors on my explorer?
Those codes are not O2 specific, they spell out that you have a vacuum leak and or lean condition. Check your air hoses off the intake and gaskets for an air leak after the MAF sensor.
The explorer was known for the j shaped vacumn hose from the passenger side of the engine just behind the throttle body and runs around to the back of the intake to degrade and suck a hole in them near the front of the engine. Listen for a hiss noise while the engine is running you will probably find that the lean codes are caused by this hose sucking air.
Search Ford Explorer Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Ford Explorer Experts