If it is a rod bearing then park it, if it breaks you will need a new block.
But tune up and rod knock would be a very very unlikely combo.
Rod knock comes from low or thin oil and rod bearing getting overheated and spinning in it's journal, spinning causes the oil holes to get cut off and then it really overheats and gets soft and a gap forms.
When cylinder fires the piston and rod are pushed down and close that gap rapidly, the metal rod striking the metal crank causes the knock sound.
If you remove the "firing" then knock will go away, well almost.
An exhaust manifold leak can sound just like a rod bearing knock, very similar.
And with the newer bearing materials and oil formulas spun bearings are not as common as they once were.
I spun a rod bearing 200miles out in the bush on an old V8, removed that spark plug wire and drove it out on 7 cylinders, didn't have to turn the crank or the rod, just replaced that one rod bearing.
That was back in the day when you could actually remove an oil pan on a 4x4 with engine in the truck, lol.