Even if the code kicked when the flex part of the Cat blew a hole? There was a small hole already and it wasn't triggering the code. It wasn't until it blew the larger hole that the code kicked.

 

So, you mean the flex pipe blew out, that would have triggered a different code, but the fact the code tripped after the larger hole, that could be the cause of a gasket fail between the exhaust manifold and the cylinder head.
I try not to reason with the what’s and the why’s, I just look for problem and then, fix it.
Unfortunately I can’t see or hear your engine here in the old interwebs, so I have to depend on you to have a look for me.

 

One4 of the criteria the computer uses to determine a miss is the O2 sensor. The O2 sensor shows a rich condition when the #1 cylinder is supposed to be firing. A hole in the exhaust will make the O2 sensor give strange readings depending on the exact circumstances.

 

So with that reasoning, Donbrew, you saying the new O2 sensor could be suspect?

what brand of O2 sensor did you buy for the front and the rear sensors on the down pipe?

 

No, saying the newly disclosed broken pipe and new cat could be the suspect

 

I believe the whole downpipe is new.

 

That reminds me; Has the crankshaft sensor been relearned? That could be the culprit.

 

Fuel rail had sludge in it pushing against injector 1. Code is clear and car is running like new all over again.

Thank you to everyone who came along on this crazy journey.

Jessica

 

Great news! It’s fixed!! So, it was dirt that caused the issue, something simple, not the wrong engine or incorrect injectors, or any other parts! Just good old dirt!
as I always say! Keep it clean and drive it often! Enjoy the ride!

 

Excellent. Glad you started at the basics....fuel, fire and compression ....has to run