after cat O2 sensors, D2

[darw_n]

I am replacing my 2 pre-cat O2 sensors on my 2000 D2...

I keep hearing that after cat sensors are not that critical?

Anyone have any words on this? Should i replace them also since I am replacing the 2 front ones?

I just don't know much on the purpose of the after cat ones...

BTW, I am replacing because I was getting P0171, P0172, and P1171 codes, and terrible milage (6MPG~) and bad sooting and smell from exhause. Plus they have 106k on them..

thanks for any input!

 

[scottagnew101]

yeah go ahead and replace the ones after the cat too. If I'm not mistaken the ones after the cat check to see if the cat's themselves are working. Taking a measure before, then after.

Best of luck,

Scott

 

[darw_n]

cool, thanks!

any tips on changing these things? i assume it is going to be a knuckle buster, and that they may be seized up.

also, I have driven a little with it burning super lean, so I am sooted up. I remember hearing that people use seafoam in a vacuum line to clean soot in the engine. Should i do something like that after I change the sensors, or will normal engine use clean it up?