1999 neon oxygen sensor

I took my '99 neon (automatic) into the shop cause my check engine light went on. they said it was the o2 sensor, but i did not need to change it because the light went off after they did the diagnostic. it's been a month now and the check engine light went back on. i would like to change the o2 sensor myself because the shop wants to charge an arm and a leg to change it. could someone tell me where is the o2 sensor on my '99 neon? and how do i replace it?

mahalo (thanks)

You have two O2 sensors, the upstream (located on the exhaust manifold) and the downsteam (located just after the cat converter). There is a special socket that fits around the plug to make it easier to take off.

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