About a year ago, I noticed some increased exhaust noise during acceleration. When I investigated, I found my original catalytic converter was totally rotted out and leaking. I replaced the cat with this one, http://www.rockauto.com/catalog/moreinfo.php?pk=268554&cc=1303322&jnid=436&jpid=0. About 2 weeks ago, my SES light came on. When I scanned for trouble codes, I found code P0420, Catalyst System Efficiency Below Threshold (Bank 1). This code generally means the cat needs to be replaced. I cleared the code, but the light came back on a day later. Called my Buick club director and he suggested a simple solution. He told me to purchase an O2 sensor extension and that would take care of the trouble code. I located one on Amazon and purchased it. Installation was easy, remove the rear O2 sensor and just install the extension and O2 sensor. Cleared the code, and it hasn't returned. Been 2 weeks now. This is the extension I used,
Curiously enough, if you read the reviews, several people comment on using the extension for the same purpose. I guess it works by reducing the sample that the sensor sees. Certainly cheaper than buying an O2 simulator.
98 Riviera SC3800 All stock except gutted air box.
1970 Buick GS455 Stage1, TSP built 470BBB, 602HP/589TQ
Best MPH, 116.06 MPH, Best ET, 11.54