I have a 96 Miata. It started to run rough and threw process of elimination I Know the cylinder is getting fuel and spark. I just changed the Crank shaft Position sensor. What could the issue be and what is my next step? I know I need to check compression and will do that in the next couple days. If the cylinder isnt getting compression which is the only thing I can think of that would be causing this do I need to pull the head? If so How do I tell if there is a valve issue or a cylinder issue or even a head gasket issue?

 

The answer for which you are seeking is............Leakdown tester. You can probably rent one from vatozone.

Follow directions and post results.