How would I know if they went bad? Even if power and exhaust flow are good? :confused:

How would I know if they went bad? Even if power and exhaust flow are good? :confused:
If they don't heat up, the catalyst is shot. So long as the substrate doesnt plug, the cat(s) will flow just fine, they just wont eat up the hydrocarbons as designed. IIRC- exhaust shops can test them with an infrared temp gun. I dunno what the desinged *up to temp* reading should be, but it's probably around 1000degF. If you've got 130K+miles on yours, that's about all she wrote. You can get an a/m cat for around $50 (ebay or where ever) and have an exhaust shop weld it in for you & your set!
G/luck
Joel

Perfect! Now I will just ask the kids to go see if it is "hot".