Tapping from engine when going from no throttle to throttle

[SteveR.]

When my engine is “coasting”, in gear or not, and I add throttle I get two or three sharp “clacks” from somewhere in the engine. I’m guessing slack in the valvetrain is causing the noise as the components go from dragging to being pushed? Any suggestions on where to start troubleshooting? The noise only exists in this transition period from closed throttle to open throttle.

Thank you!