If the black knob on the throttle body improved the idle quality, then you are covering up a dirty throttle body. But this won't affect the other complaints.

So many possibilities. Flaky AMM is one, out of range coolant temp sensor is another. Your car is one of those with engine harness insulation that breaks apart and might be the culprit. Personally, I'd start with a pressure gauge on the fuel rail to determine whether you have a delivery problem from failing pump (brushes at the end of their life) or relay (not uncommon). Even 1/2 PSI drop under any condition indicates that this is your source of trouble.