Catalytic Converter

What are the signs that you need a new cat? Would you have an error code stored or will it just be drivability problems. If so, then what error code or what type of drivability issue?

You might get a code about inefficient catalyst or something, but other signs are a groggy engine, smell of rotten eggs, rattling from the cat.

Does the rattling noise go away when the car warms-up?

I've seen cat rattling come and go, hot or cold.

One of the thing you might look up is gas millege put a full tank drive normal do you waste more gas then before or is the same. See the conveter whats is inside looks like a beecomb but since the pores are getting clog with the waste of the fumes it becomes more harded for the exhust to come out easy then before so therefore there more use of gas in order to let the exhust go out easy. But what year is the car , what i been told after ten year it recommended to change it.

You can just take it off and add some pipe in place of it. It's a great way to add horsepower and eliminate your problem.

Ahhh But the check engine light would come on and even if you try to take it off it will come back it will give you the code P0420 why because in mine i took it off and just put a pipe on it but even if i try to erase the code it would come back on

Hmmm, there has to be a way to get around that. Usually you can buy an O2 chip/wire that you plug into where the O2 sensor is actually supposed to go which keeps that light off.

Can the catalytic converter stop car from starting.
i notices rotten smell in car, car gives less mileasge around 20 in city ( i thought this may be due to v6).
I cant start car. Although looks like anti-theft is flashing, but i am not sure if it was when i tried to start it.
Any ideas.

No, it cannot (unless it's completely clogged, which is unlikely). Do the basic tests to narrow it down. Check the spark, fuel, and compression and then head off from there.

Well no but check you if it really had the theft light on if it did well you put the key in the ign. on don't start it all doors closed wait ten min. the light goes off the start the car

so the car starts or not?? be specific.

Who Me?

I think he means Ausdee.

Yes, ausdee. You have to be very specific, since I can't be there to ask you a question....does it start or not? crank or not? what exactly happens right down to the nitty gritty...no such thing as too much info!

I had a 1990 Cavalier that the cat got clogged and because of the back pressure build up a big power loss really noticable on hills, don't know if it was coolant or oil that caused it to melt but I opened a hole in it and fixed the problem untill I could replace the cat found a great price on line I believe the engine is designed to operate with the cat so I always keep one on even with the boost in power (not much loss with the new cat