Mazda Repair: 99 Miata Misfire, computer fault, toyota dealer

Question
I recently purchased a 99 Miata with 58000 miles.  The check engine light recently came on and then it started blinking and the engine began misfiring and lost power.  The Toyota dealer said it was a fouled plug and replaced it.  It ran great for about 200 miles and the check engine light came on solid but the car still ran fine.  After another 200 or so miles the check engine light began to blink and now the car is misfiring when the engine is hot.  After a cool down, the light still blinks but the engine ran fine.  The plugs are new(not sure what type).  What do you suggest next?  Thanks,  Greg

Answer
Ignition misfire is commonly caused by one or more bad ignition wires.  If you haven't already replace the wires with a good set of NGK and be sure the spark plugs are also NGK.  This may resolve your issue.  In addition, 99 and 2000 models are prone to ignition coil failures, the symptoms can be the same however I suggest ruling out the preventative maintenance parts first.

You will have to get the computer fault code read then cleared to confirm the fault.