[shorod]

Welcome to the forum!

The actual codes must have been P0302 and P0141. Misfires on that model year Lincoln LS are pretty common due to valve cover gaskets that allow oil into the spark plug wells and subsequently, an alternate path for the spark to get to the grounded head (rather than the desired path through the spark plug). This misfire is likely the cause for the P0141 as well. If you fix the misfire quickly, it probably will not destroy the Heated Oxygen sensor or catalytic converter.

Is your LS the V6 or V8 model? If the V8 model, the valve cover gasket and spark plug well seals are not that bad to replace. It's a bit more work on the V6 though. You should also plan to replace at least the cylinder #2 coil as well.

You can search this forum for more details on the valve cover gaskets.

-Rod