O2 Sensor replacement?
 

I've got a '93 Quattro 100 CS wagon, and whenever the RPMs get above 3500-4500, the Check-engine light comes on. I've read in other posts that in these older (177,000 miles) Audis, the CEL usually is the O2 Sensors... my question is whether it makes any difference to replace them (besides no CEL light), and if I'm doing anything bad to the car by driving it w/o them working (are they not working, or only at high RPMs?)

Re: O2 Sensor replacement?
 

By replacing the O2 sensors u r going to fix ur rough idle which will eventually occur if it hasn't allready. Also ur MPG must be real low right now (i know mine is about14-15mog) with bad O2 senosors. So if u have the money to replace them go ahead and do it. If u r a poor college student like me than i guess u can live with it until u save up some $$$$ to replace em.

It's not really that expensive, if you can DIY, about $70 ea. for......
 

.....Bosch universal sensors, but you have to solder the leads, and you need a 7/8" slotted socket to R&R them.

Part # and place to buy the Bosch universals?
 

If you have the part numbers, that would be great. I have 262,000 km on mine...

Thanks!