i own scanner too.. i bought one years ago..
but you need to understand how the computer thinks..
It maybe giving you one code, but there maybe 6 cuases for that one code...
my friend google'd the code, and searched high and low to fix "exhaust leaks" and "bad o2 sensors" and "spark plugs" etc,etc,etc,..
I go over there, look under hood, and plug in a small connector he had "unplugged" when he changed valve cover gaskets.
knowing what the code is half the battle, understanding how to fix it is a whole nother battle..
My cougar has a fully programmable engine and transmission computer .. talk about fun... one wrong number, and your fuel economy goes to pots...
(fyi.... The Auto Industry are crookes... most computers can be tuned to improve gas mileage and performance...)