Did you clean and tighten the battery terminals and ground wire connection?

 

Battery and ground terminals are clean and secure. I almost think that I can rule out the ignition switch because when the problem is happening I am also unable to start with my remote starter, which bypasses the ignition. I would really like to know if anyone has any information on the PGM-FI (Main) relay and if this might be the problem.

 

A bad main relay would not prevent the engine from cranking.

 

Could a bad ECM cause the engine not to crank?

 

No, the ECU is not needed to crank the engine.

Get a multimeter and test for battery voltage at both wires connected to the starter. The large wire should have battery voltage at all times whereas the small solenoid wire should have battery voltage with the clutch pedal depressed and the key in ON(III). Post the results.

 

The problem seems to extend beyond the starter, however, because the car has died while running. Any tips on what would cause the car to not crank and to shut down while running (ignition system?, ecu?) would be greatly appreciated. When the problem surfaces prior to start the car will not crank, but when the surfaces while the car is running it causes it to shut down.

 

More information is needed. Do the tests that I mentioned.

 

Did you solve the problem? Could it be the main relay?