Troubleshooting: Idle Air Control (IAC) B16A2 Engine
 

Hello All, wanted to runs something by you all to see if I am on track with my diagnoses with my idle issues. Engine is a B16A2, The engine idle bounces up and down, I have already set the TPS to 4.88 at rest, checked for vacuum leaks around the intake manifold with negative results. if i remove the intake and place my finger over the hole in the throttle body, upper right the idle smooths out to normal. once removal of my finger the idle returns back to bouncing around. Am I safe to say the problem is the IAC?

re: Troubleshooting: Idle Air Control (IAC) B16A2 Engine
 

Try cleaning the IAC with carb/brake cleaner.

re: Troubleshooting: Idle Air Control (IAC) B16A2 Engine
 

Hello failed to mention, I did go through the iac with cleaner, tested the connections to see if the solenoid trigger which it does, checked the gasket which turned out good and still experiencing the same issue.

re: Troubleshooting: Idle Air Control (IAC) B16A2 Engine
 

Have you scanned it, gotten any OBD2 codes? And/or do you know how to use your check engine light to get CEL codes?

I'm having sort-of the same issue. In the past, years ago, I got abad MAP sensor code. I simply changed out the bad MAP sensor and it worked great. This time it's something else...

one thing, for me, I need to know how to check if a IAC itself is bad. Wiring seems to be good. But with KOEO I can hear a buzzing coming from the IAC, very strange
Anyways, best of luck, hope something I said may have helped.

Re: Troubleshooting: Idle Air Control (IAC) B16A2 Engine
 

Covering up the hole in the T/B while the engine is idling should drop the idle to 500 rpm... or even stall the engine. If it idles like normal as you stated, you have a vacuum leak somewhere else.