2003 Chev Tahoe code Po430.How do I test to see if the 3way cat is bad? I have a slight mis at idle

Question

2003 Chev Tahoe code Po430.How do I test to see if the 3way cat is bad? I have a slight misfire at idle. Can a repair shop or Dealer put it on a computer and tell what the problem is?

Answer 1

P0430 Catalyst efficiency below threshold Bank 2

When there is a slight misfire even at idle this affects the catalyic convertor it may even be what is contributing to the code condition. Even if you replace the catalytic convertor and there is a slight misfire it will be a short lived catalytic convertor. You need to handle the slight misfire first. Misfire or the rough idle can be from ignition system , injectors, vacuum leaks , to a mechanical condition , Yes a shop can put a scan tool on it and in the scan tool menu there is a menu  for the cylinder contribution or the misfire events.