check engine light came on, got it scanned and was given the code P0420 "catalyst efficiency below threshold (bank 1)" (on top of my O2 sensor being bad).

anyone know what exactly this means? i though it was regarding the catalytic converter, but the man at Advanced Auto said something about a vacuum on the left side of hte engine???

any help would be greatly appreciated

 

Year, model and Mileage??
Give us some help here.
Mike

 

man, my bad.

96 disco. about 129k miles.

 

You know, there are alot of people on this site that like to help people especially when someone ask"
anyone know what exactly this means?"
So the next time you want help, be real specific ,answer questions like, "Year, model and Mileage?? "and don't be a smart *** and you'll get alot more help.
Mike

 

It may be just the O2 sensor that is bad, I would replace it and go from there.

 

I think in this case it means ( Oh Sorry ) its a 96 ect-.

 

ya, i meant it in an 'sorry' kind of way. i didnt mean to offend anyone. i appreciate the help i've gotten already. sorry to upset you mike. i meant it in the best possible way.

so you think it just relates to the O2 problem? getting the senson fixed should clear that up the hopefully?

 

Yes, I thing the O2 sensor maybe all its needs.

 

You have two on going problems, one the O2 sensors and with your mileage you should replace all of them in order to keep both banks balanced and to regain some lost power. The 420 code is a cat failure, not caused by a vaccum leak but most likely age or possibily contamination such as too much raw fuel, oil or coolant. Vaccum leaks can effect an O2 sensor but not a cat.
So that being said, go to Rover Connection or DAP on the web and look for some O2 sensors at the best prices and then go to,
http://www.completeexhaust.com/produ...roducts_id=184 for a good price on some cats.
Before you get into replacing the cats you need to find out why yours quit. First thing I would suggest is pull each spark plug and look for one that is fouled, wet or discolored from the restm that will most likely be the cause of the cat failure. If you haven't done plugs and a good set of wires lately, like Magnacor 8mm., then change them out before you but the new cats back on, and do replace both at the same time cause the other cat is most likely on it's last legs anyway.
Put it all back together and do a good decarbon on the engine and you will be set.
Mike