Cadillac Repair: engine noice, carbon buildup, knock sensor

Question
I have a 1995 sedan deville. It had a ping when I drive at very low speed i.e. take off. I recently had some BG 44k added and now the ping every now and then. I sounds like its missing something. I does not lack any noticeable power

Answer
IS or has the CHECK ENGINE light ever illuminated on the dash while driving the vehicle ?.

Possible faults:

EGR valve needs to be checked for proper operation and cleaning.

KNOCK SENSOR may be intermittently faulty.

A severe carbon buildup has accumulated on top of all the engine pistons and needs to be cleaned off via the use of a product called TOP ENGINE CLEANER or similar product.