i have a 95 h23a1 with common headers/exhaust/filter and its dropped in a 92 accord. recently when i start the car, after about 3-4 minutes of warming up, the idle will start to drop from 1900 to 1500...and it will keep on going up and down between 1900 and 1500. it has happened a couple years ago when the swap first took place, the problem then was something about the strut bar touching the engine, so we changed strut bars, and now the problem has come up and is happening more frequently. does this happen to any other h23 owners? does anyone have any advice or input? thanks

 

A bouncing idle usually means a vacuum leak. They can be extremely difficult to track down.

https://honda-tech.com/zerothread?id=152946


[Modified by DirtyLude, 5:43 AM 3/31/2002]

 

If your fast idle thermo valve is diconnected from the coolant stream, it would cause this. Just a suggestion. To check this, block one of the holes at the bottom of the inner TB and see if the problem goes away, of course while the motor is idling....