The O2 sensor part number is 006-542-96-17 & list is $162(check partsshop!!).
Takes about 15-30 minutes to replace, depending on rust!!
There are GENERIC O2 sensors that will work, this car uses a 3 wire sensor!
Diagnostic times vary due to many different items.
MOST cold running problems aren't related to the O2 sensor but to the coolant temperature sensor.

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