Easy to start the engine and . just start blocking off the tail pipe and listen for a leak. It could be at the manifold or somewhere between the manifold and the cat.

 

Going to try what you mentioned above tomorrow since I might have some time in between my son's basketball games i won't be using the car tomorrow after 9am. Today I got a different code so I ordered the o2 sensors since they are not too expensive just in case but I'm going to check the exhaust to see if there are any leaks.