1997 Ford F-150

Hi jamie
this is a oxygen sensor code. And you have one for each eng bank. Bank one is the closest to the sensor which will be the drivers side.

But for the cause you will need to do a little diag. You see it could be a bad sensor. Or it could mean you need a tune up. What it is actually saying is the fuel on that side is not burning normal. So plugs wires compression injectors gap. All mof these are possible suspects.

If you have not tuned it up recently this is where to start.

Billymac