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 ...

While relatively minor, check engine light repairs can be costly if neglected, leading to as much as 40 percent lower fuel efficiency. Metro News Service photo While relatively minor, check engine ...