My 97 Expedition has 130,000 miles on it. The check engine light just came on. Any suggestions on what I can check first before I take it in for diagnostics? Thanks!

 

Mostthe parts vendors like Autozone ect. have coded readers and will read the code for free.. If you can have it read and post the DTC it would be better than just a guess.. Most times it emissions related components.. Even a loose gas cap can set a code...