When should the o2 sensors be replaced?
 

my car has 88k on what(i believe to be) the original o2 sensors.....i have been geting bad gas mlg lately and i'am wondering if they need to be changed? When is the recommend time for them to be changed?

Also on a sidenote, how hard are they to change?( i have a 96' w/dual cats. Which brand should i buy and where is the cheapest place to buy them?

thanks guys

I bought mine from Dal everytime. Stock GM brand. They used to only be $27 each, now they are $3x.
Dal's email address is lockitup@bright.net

http://www.autotap.com/articles/Unde...n_Sensors.html

i have a single cat car, but i ordered mine online from a discount GM place. Jason Cromer will have them.

hmmmm. that website says its recommended to changed the o2's on obdII vehicles at 100k. Should i change the now anyways?

I believe that i am having the symptoms, because it says that the computer does no use the sensors until the engine warms up and i only have a rough idle after the engine warms up. and its real smooth when it first starts up and first 10 min or so. Guess i'll just have to change them and see what happens.