jr,
Your Focus is tuned for Regular Unleaded, 87 Octane. See your owners manual, or online at
http://www.myfordfocus.com/underthehood.htm
Also as seminole_kev said, it might just be that your gas cap is not on tight. I'm not sure which light that is however and/or if it's the one you see.
------------------
Ray
2001 ZX3 Owner
webmaster@myFordFocus.com
http://www.myFordFocus.com