Hi Pleican parts, replaced my whole engine. Used old MAF sensor and o2 sensor. Car revs high on cold start cuts out over bumps in the road and hard starts when engine warm. Used another second hand o2 sensor which decreased idle on cold start but still have problems. Order new o2 sensor from you guys?

__________________
This post was auto-generated based upon a question asked on our tech article page here:

Sounds like a vacuum leak. I would check if the o2 sensor is working before replacing it. When warm, it will switch from 0 to 1 volt.

- Nick