won't start about 20% of the time

What is your question?

It starts fine most of the time. Every once in a while it won't start. Below is a list of what I know about the issue. 1. I think the fuel pump is working becuase when it won't start I can roll it down a hill and pop the clutch and it starts. 2.. The starter is turning over. I can hear it turning the engine. 3. The ignition switch works becuase the lights do what they are supposed to do. 4. I just bought and replaced the ignition coil. 5. New plugs and wires 10,000 miles ago. I can not figure out what the problem is. When ever I go to fix it, it starts fine so I can't do different things to see if it starts. Plase, please, please help. Thank you, Susan