We had a car come in with complaint of very rough running, check engine light on, and very clearly lacking performance. Three fuel injectors had been recently replaced to correct an engine misfire fault.
The initial fault survey this time showed only 1 culprit – low turbo boost pressure. The turbo waste gates and control functions all worked correctly. We removed the exhaust to inspect the front catalytic converters and found the cat for cylinders 1-3 was missing the entire inner ‘bed’that does the cleaning of the exhaust gas!
As you can see in the attached image, that bed traveled downstream and plugged the secondary catalyst and fostered the boost problem. The current catalyst failure is actually collateral damage to the injector failure a month prior.
Sometimes, the domino effect is valid for automotive repair too!!