Cranks but won't Start.SOMETIMES. FIXED!!!
 

I just recently started driving my car again after it had been sitting for a few years. It had an electrical issue that would cause the car not to start at times. It wound up being a faulty MAIN RELAY that is located in the under hood fuse box. Mazda offers a higher amp relay to replace the old one. Apparently this is a problem in older Miatas. I now have an extra in the glove box.