So my 1990 Accord has had an iratic idle lately. I'm pretty sure its some sort of vacuum leak. You can hear a whistling coming from the engine bay while driving it almost sounds like a turbo. Then when you shut the car off you can hear a loud whistling like air escaping from somewhere. The idle doesn't drop lower then where it should be, but it pulses up and down consistantly, with worse jumping when the car is cold. The whistling sounds like its coming from the drivers side of the engine bay, but I cannot find out where it is coming from. Anyone have any ideas?

 

take a can of starter fluid, use caution where you spray, at engine idle, spray around lines little at a time. when engine idle increases, leak may be in that area, usually a hose or at a fitting.

 

If it just happends not to be any leaks in vacuum lines then check ur IAC valve or u Idle position senser i am having the same problem with my honda prelude. i had to IAC Valve cleaned and that took care of the problem for awhile but its back to doin it again so that would just be a temporary fix.