(Before reading, note that PCM is reporting camshaft sensor circuit failure but car rarely exhibits sputtering-at-accelleration associated with this.)
When sitting at a light, the engine normally idles at about 750RPM, after it is warmed up. For the past 1-2 weeks, every so often the tach will report between ~600 and 1000RPM - the engine will oscillate back and forth in this range, completing a full cycle between 600 and 1000RPM every 1-2 seconds. It does not always do this, and I cannot attribute any specific circumstance.
What controls the idling speed? Is it the PCM in this car? Would a simple clearing do the trick?
1988 Bonneville SSE
Stock + CD player. Why mess w/ a good thing?