Hey guys I'm new here and this is my first post so I apologize if anything is out of order. I'm looking to buy a new 4runner that has an engine knock I would like to diagnose it if I can before I buy. Right now I'm thinking its a bent rod and or a spun bearing but here is a video so you can hear what I'm talking about.


The knock is pretty bad and gets a bit faster when it revs up but sounds like it goes away for half a second when you let off the gas. The owner said he drove it over 500km already like this and he said he replaced the drivers side valve cover and didn't notice anything. I think the sound is coming more from the top more than the bottom but it was hard to tell. It's definitely coming from near the front so I also thought it might be a broken timing chain rail or a loose chain. I might ask him if I can try running it taking a spark plug out one at a time to see if it's from a particular cylinder but what do you guys think?

Thanks in advance!