I have a 99 Mustang. About a year or so ago, my check engine light (hereby known as the CEL) went on. I took it to my local shop, who charged my $75 and said they fixed it. 2 days later, it comes back ...

Oxygen sensors play an important role in your car's engine, but they aren't like many other components, such as oil filters, for which automakers provide a strict service schedule. Instead, the real ...