Hello,
I have a 2008 Honda Pilot FWD stock J35Z1, Software V48.70 170K in Limp Mode.
LOUD Metal Clanking Knocking sound coming from rear of engine, cylinders 1-2-3.
Here is what the motor sounds like:

No CEL or VSA Sound in Drivers Seat
Metal Clanking Knocking

 

welcome to the forum Sounds almost like a rod knock. Does the sound get faster as the rpm increases? Has the engine ever run low on oil?

 

I should have stuck with my gut before I started work on this.

Upstream o2 replaced with pressure gauge.
Vacuum hose removed replaced with vacuum gauge.

Your not going to believe this.

Engine Test

I am so pissed at how much time I wasted jumping around when it was right in front of my face, literally.
Now to see how much damage it caused.

 

A vacuum gauge will show it. But yeah, alot of back pressure.

 

I know right, back to the basics always works best.
No one else got this video, you been doin this for a while?
Bought this from a friend that did regular service intervals at Honda Dealership, YICK's.
Problem is conventional oil, no sludge cleaner, no injector or induction cleaner, ect.
Engine felt like half the power, knew I should've started with the cat's.....
Don't know what other damage the prolonged pressure and heat caused but starting on the cat's today.

 

I'm a retired shop owner. Been working with automotive for better than 50 years. Low power we look at vacuum and fuel pressure first thing. You can find it with a scan tool and looking at the manifold pressure. Goes up when it should go down and you know the engine is not breathing correctly. First thing then is to check exhaust.
You did good. You learned more from this than you may know.