I've been pulling my hair out recently over idle issues on my 99 EX Coupe (Canadian SI). Seems like one problem after another.

About a month ago the alternator died and I had the car towed home. After sitting for a couple weeks I finally swapped the alternator, belt and battery. When the car started I had a CEL. Scanned the car, turns out to be MAP sensor and O2 sensors. I started with the MAP sensor because I thought it'd be a quick and easy fix. I assumed because it was not drive by wire, removing the throttle body wouldn't matter... I later learned I'm an idiot. I initially removed the TB to remove the two seized screws holding in the MAP sensor. While it was off I cleaned it out with throttle body cleaner and gentle removed the butterfly to soak it overnight and reassembled it all the next day. I used a brand new TB gasket and DID NOT adjust the idle in any way.

I start the car, idle is about 2,000RPM. I searched the problem and preformed the idle relearn procedure. I believe I preformed it right as I got the idle down to ~800RPM after pulling the fuse. This is roughly where it sat before. The car idles fine in neutral. O2 check engine light is also off now.

The issue now is that once the clutch is pressed in the engine will idle around 2,000RPM. Once the clutch starts releasing the RPMs will rapidly fall a little lower than normal and I have to give it a little more gas than usual to keep the engine from stalling. If clutch is released slowly from a stop without gas ; once there is load the idle dips too low and the car would stall. I'm stumped, I've checked for vacuum leaks with TB cleaner. I've searched and my next step is removing and cleaning the IACV. I'll also look into whether or not the throttle cable is binding. As of right now, there are no check engine lights on. Any thoughts?

 

To anyone reading this down the road, I resolved the problem by cleaning the IACV (dirty) and inspected the throttle cable (it might have been moved when the throttle body came off). I also apparently have the fuse 15 issue, which is why I have an intermittent CEL. Glad to see Honda tech is still a wealth of info.