A miss under load is a good clue & makes one want to suspect a spark problem.
Maybe excessive spark gap from worn plugs, a cracked internal or external plug insulator, or faulty plug wire, or cracked coilpack.
The wet down test at night is an easy test to do for ignition high voltage break down suspects.

The miss at idle could be caused by a number of things, from sticking valves, to low battery voltage causing a weak spark, to CCDF, or intake valve deposits preventing them from seating & sealing well, or maybe a sticking PCV valve messing up fuel trim, or maybe you have a faulty IAT sensor, the list goes on & on & you may have more than one problem, so thats why a scantool is so helpful, as it can monitor so many things at once, in real time.

The high rpm idle is usually caused by an acting out/sticking/dirty/worn IAC valve, so maybe your mech just cleaned it last time. Cleaning the IAC usually doesn't last, it didn't for mine, but was a good trouble shooting step for me.