Ok. I had the Obd connected today and the live readings are disturbing. All 4 sensors are providing output and when it’s warm they all read about 950mv and the short term trim stays at o% unless I play with the throttle then it moves up and down. So, the sensors are detecting a rich condition, but the ecm doesn’t seem to want to do anything about it. I don’t understand the the nitty gritty of this, but shouldn’t the ecm be trying to trim it down? If I was looking at -20% trim and it was still running rich I could guess that the fuel pressure was to high for various reasons maybe, or a vacuum leak etc, but it’s not even trying to correct it. What the? Black smoke is visible at the tailpipe at idle and obviously it’s running rough.