3.0 v6 engine noise knocking

[elliot2fastjame]

i just bought a 1995 4runner with 141k on the orig motor. I drove it home about 60 miles and decided to change the oil just as a precaution. i put the normal 10w 40 in it and heard it making a noticeable knocking noise at a certain rpm while driving and at idle after it gets warm, but when its cold you cant hear it. however my girlfriends grandfather was the one who drained the oil as i went to purchase the new stuff so i didnt observe the old stuff however i assume it was super thick because it hid the knock pretty well. Now i am currently trying to pin point the problem. I have talked to a few others (not certified mechanics) but they told me it could be the timing belt slapping, something in the valve, rod knock, a spun bearing or something along those lines. i am more then frusterated with this problem but am willing to sort it through. will a odb1 tool tell me what the exact problem is? if not what is the most efficient solution, and please keep in mind i am strappped for cash!

thanks in advance for your time and cant wait to hear some feedback!

 

[TGS4runner]

I had a similar issue which turned out to be torn pieces of the timing belt slapping against the plastic cover. There should be a small removeable plastic lid on the face of the cover. Opening that reveals the tensioner as well as a good idea of the belts' condition. The belt is pretty wide for a timimg belt. When they get old they stretch enough to start walking inward consequently chewing away the belt as it overhangs.
I am not sure whether valve lash is adjustable on those heads.
The ECM may be pre-OBD so you'll need to find someone with either a more application-compatible scanner or an old relic such as a Snap-On MT2500 scanner.
Rod/piston pin knock will be a hollow low double knock.
May also be a possible exhaust leak.