One evening after using my 740 wagon that afternoon, it refused to start. Since it had been idling rough, I changed plugs, wires and cap/rotor and later the ignition module. No change, so I threw a fuel pressure regulator at it: Nothing!

I got busy with other things and the car set for a few weeks.

To see if the timing belt had skipped a tooth or two I had my wife using the starter to align the timing marks. It started. It still idled rough and there was a slight roughness at highway speed, but it ran somewhat like it had before the plugs, etc, were installed. We used it for about 10 days and then it failed to start again.

Can the crank position sensor be checked on the car or by a shop if I removed it? It seems to be an intermittent electronic problem. Are there any other components that are likely to cause this problem?