I have a 92 honda prelude si with h22a1 motor the engine idles up and down, also sensor rusted in half on back side of block under intake manifold looks like knock sensor. Anyone have idea? also the black air box under the intake manifold has a a small black air control that has an airline running to it that is rusted through anyone have and idea what this part is?

 

https://honda-tech.com/forums/honda-prelude-4/end-all-idle-surge-bounce-etc-problems-thread-1979500/

i present to you, thee great mgags.

 

i have put all brand new airlines on i was asking about the knock sensor location and the other part listed can you answer any of those questions if so i appreciate it

 

Tightening the screw on top of my throttle body solved my idle from bouncing.