my car won't start

I have a honda s2000 2002 with 90,xxx miles. My car will turn over and over but it won't start. At first I thought it was the kill switch and it didn't fix the problem when i got it removed. since then i have changed the battery, alternator, starter, and still nothing it won't start! some things that i have noticed is that like yesterday when it did start it cranked a couple times and then it finally started, and it was at high rev like 2,000 rmps and then as the car heated up the rpms would go to normal idle