Three weeks ago, the car went in when the light came on. I had the codes, something like the cyl. 6 misfire among others. The dealer had to call Nissan and they said to replace all the coil packs. A week after that, the light comes on again. O2 sensor bad. So they replaced both. So far, so good, but it's only been a week. I suppose the O2 sensor could go bad if the was a misfire? Wonder what caused all this crap? Bad gas? Hard driving? Anyone else have these problems?

There seems to be a strong correlation between the Cylinder 6 misfire and the O2 sensor.

I hope these repairs are being done under warranty.

These two episodes may have been coincidence. However, there could be a linkage. If one or more cylinders misfires you would have incomplete combustion with the consequence of crusty deposits being formed on the inside surface of the exhaust system including the Oxygen Sensors.

The coil packs are electronic devices and are not affected by bad gas or hard driving any more than your radio or headlights.

Yes, full warranty. And no mention of the intake or cat. I spoke with the mechanic who was a yonger kid. Seemed cool but maybe not all that knowlegable. At least he deferred the problem to Nissan. They even gave me a new key under warranty. Wife broke the ring somehow.