Engine warning light - oxygen sensor?

My engine warning light has been on for several thousand miles - the dealer told me had to replace 4 Oxygen Sensors for about $850+ (I would rather drive a Dodge Colt then give this dealer that kind of money).

I have found cheaper parts and those people told me that it is unlikely more then one has gone bad. How do I determine which one is bad and are they difficult to replace - is there information on how to replace them.

Thanks for your help and Happy New Year

You might want to try some other dealers. I had a problem with my oxygen sensor too, turning my check engine light on... I went to a dealer and wanted to charge me 500$, i went to some Audi dealership afterwards and ended up one tube being sliced... it costed me 32$ to change it. :D

Cheers,
TrAiAn

O2 Sensors are piece of cake to change. Just unscrew the bad one and put in a new one. To find out which one is bad, you can either have a good and respectable mechanic tell you or you can figure it out yourself by trial and error. Replace one O2 sensor and if the light still comes on put the old sensor back in and move the new sensor to the next location.

Did you ever solve the egr problem, clogged port in manifold and/or solenoid.

makesure it's not the mass air flow sensor lot's of them are going bad, When you scan the car the code will come up as Up stream o2 sensor but realy it's the MAF sensor.

there are 2 diffrent types of o2 sensors post cat and pre cat so the you would not want to go with trial and error i would look around for a person with a odb code read out and then it will tell you if its pre or post cat and save you a 150$ if it is the post i wouldent worry to much cuse they dont do much. pre i would worry about because eventually you could get valve damage