Noise from Engine Bay

[jabranko]

Hello Everyone, I'm new to this forum.

I notice this something that almost sounds like a clatter/knock type noise, it's not extremely loud but it can be heard from outside the car or inside the car with the windows rolled up and radio off in a silent area. It's only when the car is in drive or reverse and only with my foot on the brake, if I let off the brake and let it start idling and moving the car the sound disappears immediately. Also it disappears if I put it in neutral or park. The other annoying thing is it comes and goes, but it usually doesnt happen from a cold start, only after driving around for a bit and coming to a complete stop (the sound doesnt start even when decelerating, it's only when the car comes to a complete stop and then it "kicks in") in a parking space or at a light and even then sometimes it doesnt occur which is why my last 3 trips to different toyota dealers have come back with no results because I'm having trouble duplicating it at the dealer every damn time. I found a post similar to this but there didn't really seem to be an answer.

From what I've read a rod knock will get louder as you accelerate so I don't think it's that because the noise completely disappears when I even tap the gas. I've found many rod knock videos online and my car sounds nothing like that but I can't find any videos that show what a main bearing knock sounds like or when it would occur.

So the point of this post and my questions are-
1.What kind of knock would only happen in drive or reverse at a dead stop and go away when accelerating? (if it is even a knock)
&
2. Do main bearings knock only when stopped in gear and disappear when accelerating? and would any kind of knock happen only sometimes? Under what conditions does a main bearing usually knock?

Thank you in advance.

[vgames33]

Check all the heat shields on the exhaust system. 90% of noise complaints I receive are from heat shields that have rusted away and started flopping around. They can come and go, and generally only rattle in gear at idle.