1992 Honda Accord idling problem

Hi jpopiel,

Thank you for the donation.

When idling surges, it is due to excessive air getting past the throttle body. As you have replaced most of the items related to this, there are a few things that you need to check.

1. Vacumn leakages. Check PCV, brake booster, manifold gasket.
2. Idle adjust screw.
3. IAC and fast idle. Remove the air intake hose. Start vehicle and warm up engine. Close the lower port inside the throttle body, if idling stabilises, the fast idle is not closing correctly. Check if the coolant hoses are clogged. Check if coolant level is correct in radiator.

If above does not help, close the upper port. This is for testing the IAC. If both does not help, cover the complete throttle body opening and if engine does not stall, there should be a vacumn leakage after the throttle body.

For some models, at end of intake manifold there is a vacumn pump and that tends to leak causing the idling to increase resulting in the surging.