My 1991 Montero 3.0 automatic will not start. The engine light came on and I pulled over to see why and didn't find anything and then it would not start (It would turn over though). After messing with the coil, battery connection, it started back. Now it will turn over, but will not crank. I disconnected the coil wire from the distributer cap and it will spark every now and then. I know it could be the ignition module, coil, or computer. Is there any way to check and narrow down the possibilites.