Thank you. The rockers aren't loose. I guess I will just drive it until the condition gets very bad. I don't want to invest this amount of money for all the cams and other valvetrain parts. Getting a junkyard engine might be cheaper than repairing the current engine.

 

Try removing the crank sensor and slowly rotate the engine using the crank pulley bolt to inspect the tone ring for the sensor. It will be easier with a helper.

If all the other electrical and mechanical components have been ruled out it could be a damaged tone ring.