Catalytic Converter bad or something else?

To give you some perspective, I own a 2006 Toyota Tacoma 4L V6 and there is this weird shaking that is coming from the back of my truck when I idle. The engine and transmission mounts are fine, and I checked them. But the rattling is felt throughout the truck, so I am assuming my catalytic converter. What do y'all think?

 

I'm confused, is it a noise or vibration?

Typically when a catalytic converter breaks up it sounds like a marble rattling in a coffee can, if one is coming apart sometimes you can bang on the exhaust when it's cool and tell where it's coming from.

 

It is a vibration. Not a noise. I am going to replace my power steering pump tomorrow (leak) so I will bang on exhaust to see if there is a rattle. It is like rough idling, but my RPMs only sit around 700 to 500 so I have no clue honestly. Maybe I am just being paranoid because I am about to head on a cross country trip back home (finally getting out of the Navy).

 

Does it only do it in drive or reverse or does it do it in park too?

 

It only happens in park. There is a bit of a delay between the gas pedal and the engine, but I don't know if that is related.

 

It may just be that the idle is a bit low due to a dirty throttle body, idle should be 700-800 at operating temp in park and ~550 in drive.
I think the first thing I would do is clean the throttle body, disconnect the battery for a few minutes, reconnect it, and let it idle for a few minutes after it reaches operating temp (minimum temp for idle learn to begin is 176F).

 

I will give that a shot tomorrow. I will let you know how it goes.

 

Can't hurt to inspect the converter's heat shield while you're at it. Mine was more a noise than vibration but mine was loose. Toyota just removed it.