Last week I had a no start condition and a check engine light on. I pulled codes and found Code 1-3-1. I replaced the crankshaft position sensor, which I believe is referred to as an impulse sender in the wiring diagram. That seemed to clear up the issue and she ran great until this morning, when I initially got a no start then after several attempts she started but I had a check engine light and a code 1-3-1 again. I think it is doubtful that the sensor is bad already. The wiring diagram seems to indicate that the impulse sender feeds directly into the Ignition control unit. Which seems to indicate that I either have an issue with the wiring leading to the ignition control unit, or the unit itself has an issue. Has anyone else had this issue, could it be as simple as a bad coil, cap or rotor, maybe a hall effect sensor? Does the Ignition control get an rpm signal from more than one source?

Thanks in advance,
Don