StevenH

I just found out my first one is bad and I was wondering if I should replace it right away or if it could wait a little while. I think it may make the car run a little rich but is there anything else I need to worry about?

JAFO

in general you'll notice a drastic drop in gas milage. for me it was from 27 mpg to 19 mpg.

StevenH

Is there any chance I may be able to clean it off to help it have better readings again? I was driving the car for a while with out MAF and a massive boost leak (the charge pipe wasn't on the turbo) which may have coated the thing in unburnt gas. I'm probably wrong but it may be possible...

johnAWD

Since the ECU is probably seeing a signal which is 'out of spec', you will most likely run rich. Probably quite rich. Self-preservation mode.

Replace it.

johnAWD

Not really. The O2 sensor compares the content of the exhaust stream with that of the air outside of the exhaust - ie, in the engine compartment.

Once they go, they are gone. Especially if the top part of the sensor is polluted with any type of chemical - coolant, fuel, etc.

Replace it. They are cheap.

StevenH

They are cheap!?!? I'm going to buy it at cost and its more than $150

201-A4

It doesnt have the proper plug, but you can splice it in.