Hello everyone hope all is well I have a situation with my engine...my 84 trans am is making an unusual noise....not so much like knocking but more like twang sound...kind of like a noise simular to the noise a hot exhaust makes when cooling...only louder than that...the noise does increase (get faster) when I idle up the engine....I know that it is not a rocker arms cause I seated them with the covers off while the engine was running....any thoughts of what could or would be making the noise...thanks for you time and input to what it might possibly be...