Eating up cats...

[Mark B]

Just found out that I tore up my 2nd cat in 2 years. They keep breaking up inside & hollowing out. What can cause this? What should I check?

[Doubleome]

A long stick and no emissions testing.

[Mark B]

Haha... Only thing is I dont want to hollow it out. The engine is doing it for me.

Im pretty sure running lean or rich causes this...But how can a car with a computer & an 02 sensor run lean or rich? What if im burning a little oil? Could that do it? Anything else?

[Joe 1320]

The leading cause is unburned fuel in the exhaust that gets "lit" by combustion events from a subsequent cylinder or an overly lean condition that burns the catalyst. Look at some kind of data logging to look for strange peaks and valleys in the fuel mixture.... could be either fuel or ignition.

[Mark B]

Thanks Joe... Looks like im breaking out the ALDL cable again.