'97 Protege will not start

OK, I have a '97 Protege 1.5 with 120K miles. I have had the car for 7 months and it has become harder and harder to start over that time. Now, it just won't. It cranks, fires once, and dies. After 10-15 minutes of cranking, I can sometimes get it to start. It does not matter if it is cold or hot. The only time it starts is if it was driven within the past few hours. Then it seems to start and run just fine. In addition when it does start after this hard staring issue, it runs very rough for a few miles.

I have replaced the following parts:
Fuel pump
Fuel filter
Fuel pressure regulator
Dist. cap
Dist. rotor
Spark plugs
Ignition wires
Crank position sensor

I have checked the following:

The fuel pressure is good
Compression is good on all four cylinders
Spark strength is good
The timing light tells me all four plugs are getting juice and the pattern is consistent.
It does not start on starter fluid.

It does have a CEL that references a bad cat. converter, but it goes out now and then, and it starts hard even when the CEL is off.

Any thoughts?
-Chris

Check your ignition coils. Are you sure the spark is strong?

If you have a strong spark and you use starter spray, it should start no matter what. Did you spray the starter fluid close enough to the throttle body to do some good?

Check for vacuum leaks and clean your mass air flow sensor (or whatever they call it on the mazda).

Had to replace the distribtor on my 97 to cure the problem.

If the converter is clogging the exhaust, nothing will get it to start. You can drop the pipe and check the converter, usually the back side of it starts breaking away and travelling down the exhaust and finding a spot to get stuck. On a system with two catalytic converters, murphys law states that the front will break up and clog the second. If you find pieces of it broken off you should get them both replaced. The precat/warmup cat is usually the one to go first. You can hollow out both cats if you want but it is a bit illegal. They wouldn't charge you with anything most likely but they will make you get converters when you go for emissions testing.