I really need your help Scotty, Bob's 2000 accord with 210k miles all of the sudden has jumping RPMS when sitting in park after starting. It starts at 1.9k rpms and then starts bouncing up and down from 1.2-1.7k after 30 seconds of smooth cold Idling. the engine speed is clearly changing without a throttle cable moving. It wasn't like this the last time I drove it when he first went into the hospital. Also the automatic shift button is frozen solid. He told me to hammer that thing and It didn't work. It is a new transmission, and the shop will probably unseize that atleast.
![motorcycleman [BANNED]](https://i0.wp.com/i.postimg.cc/fLKMkt8H/ban-user.webp?resize=96%2C96 "motorcycleman [BANNED]")
I would take off the throttle assembly on top of the intake and thoroughly clean the whole thing they will often do that when they get carbon build up and small holes get clogged up. But of course also check for vacuum which air vacuum lights will do that anywhere under the hood
Now after driving I see it has a problem when coasting down itll clunk in gear, and The idle goes back to normal warmed up when put into neutral.