The main symptom is a complete lack of power. By lack of power i mean holding the gas pedal to the floor and only going 15 miles per hour. The car will idle well but no power hardly at all.
Another symptom is rattling. If you strike the bottom of the Catalytic Converter wil a rubber hammer you will hear rattling from inside the converter. That indicates that the honeycomb matrix inside the coverter has broken apart.
Finally, if you ignore the loss of power (it gets progressivly worse) eventually the car will not even start.
Please keep in mind that the converter does not instantly go from good to plugged. It takes time. Mostly you notice the power loss on top speed first.For example only being able to go 50 m.p.h. . Then later on only 40...Again, the power loss gradually gets worse.
If you really think the converter is plugged then you can disconnect the exhaust in front of the converter and see if the power returns.
Also please keep in mind that some cars have "pre-cats" or "mini-oxidation" converters. Thay are a small catalytic Converter in front of the main converter. They go bad as well.
Matter of fact, the last car i had with a bad "cat" it was one of those pre-cats. It was on a Toyota.
One last thing...Mercedes Benz has a recall on the Converters on some models. You can get it replaced fo free. (normally $800) About a year ago i had a Mercedes come in with a top speed of 5 MPH. I removed the cat and the guts of the converter poured out like coffee grounds. Free replacement from the dealer
Some cars have up to 4 cats so keep that in mind also.
best of luck
^_^
Some symptoms of a bad catalytic converter on a 1994 Lumina are engine stalling, engine backfiring, no start of engine, and poor power pick up. If the catalytic converter has rust holes, the vehicle will also be very loud when running.
Hard starting, loss of power, poor fuel mileage are symptoms of a clogged converter.
Hard starting, loss of power, poor fuel mileage.
There's no possible way to pass inspection with a bad catalytic converter, if if you find out you have a bad catalytic converter during your inspection you have a chance after you after you have replaced the catalytic converter and the inspection no no charge/free!!
Well . . . you know the problem was not caused by a bad catalytic converter. You could experiment with replacing your oxygen sensors, next . . .
Vehicle "bogs" and has no power
No, the catalytic converter is downstream from the EGR valve so it has no effect on it.
Transmission torque converter or an exhuast catalytic converter?
A bad coil can damage a converter. If the engine is misfiring, it will cause raw fuel to get into the converter and that can cause failure.
Hard starting, loss of power, poor fuel mileage, a blowing sound under hard acceleration, and the converter will get very, very, hot.
Check engine light, rattle noise, low power, change in fuel economy,
if we are talking about clogged catalytic converter; 1. Lost of power 2. Engine warm up fast 3. press gas pedal, but engine runs low RPM it depends on the % clogged