Idle goes up, Idle goes down black smoke comes out! HELP PLEASE

My 2000 v70 XC 162k , At idle the RPM started hunting ( moving up and down) some black smoke and some soot came out, but it stopped after about 40 mile. Now, the car is vibrating when at idle and when accelerating, but the vibrating Stops when i mash the gas. It doesn't vibrate as much when out of drive. I also noticed the CEL light will flash sometimes. The codes are for both upstream and downstream O2 sensors. The car sounds like it's puttering.Can the O2 sensors be causing my problem or is it the ETM? The exhaust is much warmer than usually. New spark plugs ,temp sensor and thermostat. Thank you

What are the codes? If they indicate to upstream and downstream O2 sensors, check the sensors. It could be the O2 sensors, or it could be other parts. Also check systems related to the sensors. Then test if the cylinder pressure is within normal range, if its ok, check air supply system leak, and look inside the cylinder. We have this Honda Odyssey with similar problem in our shop, turns out to be deformed inlet valves in cylinder.

Yes they can do this