My 87 GN made a rattling noise from the cam sensor when the car was cold and then seem to subside as the car warmed up. I had about 90,000 miles on it when it started to make this noise.
I have heard of this problem before. I changed mine out and the noise went away.
It could be the culprit. I do know they make cam sensor repair kits so you don't have to throw the sensor away.