Scan it even if the light is not on. It could be an intermittent code. PCM detected the problem then when the condition was not there after a few drive cycles, it turned off the CE light. And scan just in case a code is getting ready to come on (just lurking there, with no CEL)
And maybe the gas cap is not properly closed (or broken seal), the high rpms (with vibration) could detect that. Try checking your gas cap too.
Some CEL info is in the owners manual. To download free
www.fleet.ford.com
Post the CEL after scanning it.
Edit. Battery MIL, charge light? At high RPMs. That could be floating "brushes". Alternator about to go.
