Check engine light comes on, then goes, Very abnormal.

The check engine light was coming on. The dealership said it was the thermostat then changed their minds and said the oxygen sensor was the problem. I replace the sensor and the problem corrected but this was only the beginning a my nightmare. The car started burning oil (which is likely why the sensor went). Ultimately I was informed the vehicle needed a new engine which is totally ridiculous. Very poor quality for a high end vehicle!