I started my 2003 F250 Ford V10 eng with 105K miles. One owner, looks new. The check eng light came on and stayed on. I took it into the Ford place here in Yuma and 3 hrs later they said I need a new ...
If I'm away from home and get a check engine light I will always carry a code reader (or you can go to Auto Zone, Orileys, Advance, etc..). If it's running good I will fix it myself or wait till I get home.