'96 Civic DX coupe D16Y7 engine.

When started cold the idle fluctuates from fast (what seems a normal fast
idle) to slow (almost stalling.) It straightens out after a minute or so
and then idles fine.

I removed the throttle body and gave it a thorough cleaning with tb cleaner.
I also removed the Idle Air Control valve from the tb and cleaned it.
Although the car ran slightly better, the idle problem is still there.

I'm suspecting a faulty Idle Air Control valve but I wanted proof before I
plunk down $150 for the parts. So...I followed the procedure in the service
manual to jump the service connector and watch for codes blinked through the
check engine light. Nothing! When the service connector is jumped the check
engine light stays on solid - does this mean there are no codes being thrown
or does it mean something else?

I also want to check for vacuum leaks. Anyone have any tricks to share on
this.

Thanks in advance for replies.