How do I know if I have a bad CAT CONVERTER?

[bratt]

after driving my dodge ram around for the day I can hear the pipes sizzling and some faint popping noises. I heard this could be a sign of a bad cat converter? does anyone know.

One time I think I could hear the oil boiling for a minute there.

[rockwood84]

if you have a bad cat it should throw a code. have the codes scanned . do you have a oil leak that could be getting on the exhaust this will make a sizzling sound as the oil is cooking on the exhaust pipe.

[bratt]

Yes, Sometimes it will throw the 02 sensor code.

[rockwood84]

which bank? as you should have 3 o2 sensors two before the cats one after. if the 02 code is coming up as the one after the cats then you could have a plugged cat or if you have dual exhaust then your gonna have two cats. i've had a plugged cat glow red before this might tell you which one it is .

[wafrederick]

Doing a back pressure test can tell too.You can get a back pressure gauge at any parts store.You remove the oxygen sensor and put the back pressure gauge in it's place.Do this with the engine running.