Is it throwing any codes? Even the old non-OBDII Miatas have codes that can be displayed.
If you open the oil cap and crank the engine, do you see the cams moving? If not, your timing belt broke.
Do you have spark? Don't pull the wire off to check, you'll damage the coil pack... instead, put a plug in the end of the wire and lay it on the valve cover and see if you have spark on the plug. If you don't have spark then you have a coil pack issue or a sensor issue.