OBD 42 Errors

Have a 1990 Century that has begun running bad and generating 42 errors with a check engine light. If I drop the codes and it starts without a check engine light, it runs fine. If I restart and the check engine comes on, it once again runs lousy and generates another 42 code. On the 3.3L engine where might I find the cam sensor? I found the crank sensor. Any ideas?

My info shows, you don't have a cam sensor. I believe you have a dual crank sensor, puts out two signals.

The code 42 refers to the spark timing.

You are correct about the dual sensor. Just read about it in the Haynes manual. Now this morning its starts and runs ok. Maybe something heat related. I hate those intermittent ones.

My 42 errors are indeed related to the temperature of the engine. This morning with the engine cold, it started numerous times without a check engine light. The last start I let it run till the fan cycled twice, nice and warm. It idled just fine the whole time. I turned it off and back on and once again a check engine light and a lousy idle. I inverted a can of air to produce a freeze spray to reduce the temps of the crank sensor and the ignition control module with no luck. I'm now looking at the temp sensor since the ICM uses its variable values. Any ideas????