This is a problem I have noticed since day 1 (i got the truck used, not new). I asked my dad about it (hes decent with engines) and he said its probably just some bad fuel or something but many months and many tanks later, I still have this engine clatter. I notice it in the low RPMs range and it seems to disappear as my rpms go up. Its a rythmic clatter and I have no clue where it's coming from. What are the most common things to check for this? Thanks!

Oh yeah, 2000 Tacoma sr5 5vze synthetic fluids (oil changed every 3k-5k miles), regular gas