How do you know when you need to replace your catalytic converter?

A catalytic converter could need replacing for a couple of reasons. If your municipality require emissions testing a defective converter could be the source of fail emissions problem but the most common reason that a converter is replace is plugging off the exhaust system lowering the performance of the engine. If your car appears to run properly but lacks power a clogged catalytic converter could be the source of the problem. One of the quickest ways to verify this is an intake manifold vacuum check. If the vacuum reading is low and steady this is an indication of a plugged converter.