CAT Failure

[martiy]

Will a failing CAT cause poor idling, like a shudder, lumpy exhaust note etc? (ECM reset already done) The right exhaust on my car is noticeably rougher than the left, but only at the lowest point in the idle (950rpm) all other rpms are smooth.

Is there any tell tale signs for CAT failure?

Edited October 28, 2006 by martiy

[outtamyway]

Will a failing CAT cause poor idling, like a shudder, lumpy exhaust note etc? (ECM reset already done) The right exhaust on my car is noticeably rougher than the left, but only at the lowest point in the idle (950rpm) all other rpms are smooth.

Is there any tell tale signs for CAT failure?

I had a "lean left bank" ECU code come on when my LH Cat went. Didn't really idle real bad but I would think if it is collasping or blocked in some way you might experience more erratic idling. By the way it is covered by the emissions warranty for up to 8 years or 80K I believe. It is covered in the owners manual under the emissions warranty section.

[Zhastaph]

When 1 of my cats gave way it began by feeling a little strangled high up the rev range, then after about 10 miles or so started feeling massively strangled high up combined with making wooshing noises.

It had no real effect on the idle other than not a lot in the way of gasses came out of that pipe and what did felt very hot.

[airbusdrvr]

Will a failing CAT cause poor idling, like a shudder, lumpy exhaust note etc? (ECM reset already done) The right exhaust on my car is noticeably rougher than the left, but only at the lowest point in the idle (950rpm) all other rpms are smooth.

Is there any tell tale signs for CAT failure?

I have the exact same thing on my 99. I haven't noticed any performance loss at high speed. I did have to use some higher octane racing fuel at a recent track day and have been told it can damage your cats. I hope that didn't happen. Let me know what you find out.

[atgnat]

if the cat is going bad, you will throw off a ton of engine codes.