Check Engine Light

I have an intermittent 'check engine' light. It came on for about a half
hour in the middle of 3 hour drive. It was out well before the engine was
stopped and turning the key back on to accessory did not result in an error
code flashed by the check engine light (per miata.net it should on this '95
triple black). I recently had the timing belt, ac and alternator belt, two
front hoses, crank seal and two front cam seals, ignition cables and plugs.
The power of the car was significantly increased after the repair, probably
due to the new cables. Any suggestions welcome. Thank you!