My 'service engine soon' light just came on today. Took my truck to Auto Zone and they told my that my fuel trim bank 1 is running too lean. Told me that I either needed (1) oxygen sensor, (2) spark plugs, or (3) fuel injectors. Just wanted to get any input from this site to see which thing I should try first. Any suggestions?

 

You likely need none of those parts.
The OX sensor is reacting to excess air at some point in the intake tract.
The excess air causes the fuel trim table to shift out of limts.
This is what sets the code by indirect detection of the fault.
The OX sensor is the only way the system has to tell about the fault.
This is the danger in running with a code discription without knowing anything about the back ground of what can cause it.
Good luck.

 

So excess air is getting in somehow through a leak of some sort? I should have my husband look at the intake tract? Hoses?