2000 2.4L Timing Chain Tensioner piece in oil pan

I am curious how this turned out for you. The same thing happened to my 98 Ka24DE only worse, all the intake valves needed replacing. In my case the head needed removed to do the valves but had it not skipped time, I would have just replaced the lower tensioner and guide. This can be done according to the Haynes manual, by removing the upper and lower timing covers and just let the head gasket stick out.

You didn't say where you found the pieces. Is the lower timing cover off? Did you remove the oil pan?

Seems like the oil in mine always got dirty quick, possibly due to the ground up chain tensioner parts. Seems like it has been noisy for a long time. At one time I replaced belts, idler bearings, and alternator trying to eliminate noise but now think it was timing chain and related parts. Hopefully with another oil change yours will clean up.