Hi,
When this happens, is there anything noticeable that is out of the ordinary? For example, a rattling sound under the vehicle? An odd smell from the exhaust?
I have seen the insides of the catalytic converter come loose and block the exhaust on and off. It's a thought. Without diagnostic trouble codes, we have to inspect one circuit at a time (or at least consider one at a time).
Take a look through this link and let me know if anything seems to mirror what you experience.
https://www.2carpros.com/articles/bad-catalytic-converter-symptoms
Let me know.
Joe
Saturday, May 29th, 2021 AT 6:53 PM