Almost sounds like a knock too. Could be valves need shims and injectors.
Keep an eye on your oil.
This to check :
1] PVC valve.
2] vacuum lines
3] compression check all 6 cylinders.
See if you can pinpoint the exact location of the tick.
Injectors are known to be noisy too but that sounds me more like a valve ticking.
If all that checks out good.
Try locus or some other name brand injector cleaner. [ doubt it's an injector]
You can also jump a oil grade to like 10w 30 or remove a quart and add locus heavy duty oil stabilizer.
If you add locus and it quiets down some you definitely have some engine wear.
Just a few thoughts.
Sent from my SM-J337V using Tapatalk
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7 3rd gens listed in the build thread (2 are parts mobiles)
Build Thread:
https://www.toyota-4runner.org/3rd-g...os-builds.html
Brillo's Bucket Fluid Ex changer:
https://www.toyota-4runner.org/3rd-g...ml#post3358086
Sparks Plugs Wire and Coil Information:
https://www.toyota-4runner.org/3rd-g...on-5vz-fe.html