I'm not sure I understand what you mean by separation in exhaust after converter. Can you explain? It honestly could be a plugged catalytic converter. That will cause the symptoms you mentioned. Take a look through this link. It describes symptoms of a plugged catalytic converter. See if it mirrors what you experience. The second link explains how to test a catalytic converter.
The second link explains removal of the converter to test. However, if you remove an oxygen sensor before the converter, often time that small amount of opening will created a noticeable improvement if the converter is plugged.
Additionally, I would imagine the check engine light is on. If you haven't already, the computer should be scanned for diagnostic trouble codes. If it is a converter issue, chances are you will find a P0420 indicating converter operating below threshold.
Let me know exactly what you were referring to, and if it is with the exhaust, try the test I suggested and let me know the results.
Friday, May 22nd, 2020 AT 6:07 PM