I put this in the tuning section but guess its more appropriate here.
Issue:
During a cold start with no o2 sensor plugged in the car fires up at 1500rpm then makes its way down to 900rpm. Perfect, no issues!
Now we do it again but this time install the o2 sensor. Fires up at 1500rpm then makes it way lower then jumps up, goes down, jumps up, rinse and repeat. When the rpms go up the car leans out, when the rpms drop the car richens. It does this until the car is warm.
Once the car is warm you can start her up and it idles perfectly.
o2 sensor is brand new. I was running without an o2 for 2 weeks until I received it today. Once I put it in/cleaned the codes the car would idle as described above. Also to note, this happened with the previous o2 until it crapped out on me.
Can this be pointing to the MAF?