What is this engine tapping noise?
I think its a knock more than a tap. My bet is the “Main Bearing” in the bottom of the block GM’s are or at least used to be infamous for that. I think the bottom end of the motor will need to be rebuilt in order to relieve the noise. Try some “Marvels Mystery Oil” it should quit it down for a couple days. I drove my blazer that way for over a year but sold it before it went out for the record i told him about the problem.
