Weird knocking noise

Hey all, I’m new to this subreddit! Have any of y’all had issues with a knocking noise coming from the engine when accelerating? It doesn’t happen every time, but it does ONLY happen when accelerating. It sounds like 5-7 pulses in rapid succession, with the last pulse ending on a higher tone. Whole thing lasts 1-2 seconds. Really concerned it’s causing damage to the engine.

2003 Town Car with 175k miles

Thank you!