The motor will idle down low but never cut off, then correct itself and do it again. Can't tell what the RPM actually is because the tachometer is erratic and all over the place. The motor runs good, just idle issue. Would like to know how to fix both the idle and the tachometer.

BnNC

. Erratic tachometer readings can be caused by a failing Ignition Control Module (ICM); therefore, test/replace the ICM:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-46563-4.html#post265896

. Ensure the Idle Air Control Valve and hoses are clean:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-46563-7.html#post1054149

The motor will idle down low but never cut off, then correct itself and do it again. Can't tell what the RPM actually is because the tachometer is erratic and all over the place. the motor runs good, just idle issue. Would like to know how to fix both the idle and the tachometer.

BnNC
That fixed the tach... thanks
I cleaned the ACV, which wasn't dirty. Still having the idle issue. Could it be an O2 sensor or vacuum problem?

See if this link helps:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-46563-7.html#post842969

Yes, vacuum leaks could definitely cause the problem you describe.

. Clean throttle body.
. Run a compression test on engine to check valves and rings.
. Adjust valves.