what are some signs of a clogged cat converter?

[tysn]

i took my xt out for a drive last night and i noticed in 5th gear i went to climb a hill i have climbed many times before, the car was losing speed going up it, never happened before. then as i came down the back side it wasn;t accereration like it normally did. then after a while going downhill it started pulling along pretty good, any thoughts? i know the car does have a exhaust leak around the first cat area. ill be looking at that tomorrow. any insights would be greatly appreciated.

[hooziewhatsit]

when my cat element came loose and blocked the exhaust, I had NO POWER. I could only accelerate over 35 going down hill. There was also a distinct louc 'whistle' from 'somewhere in the front of the engine'.

 

I used a rubber hammer to gently tap the cat, and heard the chunks of the element bouncing around. After that I pulled the Y pipe and cat, and really heard it rattling around.

[bustle]

It might run hotter than normal too if the catalytic is plugging. Power loss is usually the one you notice first.

[thealleyboy]

Haven't had one clog on a Sube yet, but the symptoms described above are typical of what you'll encounter.

 

Another possible sign would be 02 sensor problems - either fault code, or outright failure. Black smoke out the tailpipe (from running rich) could be the result of a clogged cat.

Diagnosing these can be kind of tricky. In my most recent experience, I only discovered the problem by process of elimination. And this was only verified when the pipe was removed. And of course, you can easily destroy the 15-20 year old OEM pipe trying to take it off.

Makes complete sense after the fact, but these can stump you when trying to chase down the problem.

good luck, John