1997 Honda Accord Sdn idle surge

I have a idle surging problem

Clean throttle body and check IAC.

This vehicle is notorious for IAC valve causing idle surge… It is either the IAC itself OR you have air in your cooling system. I would look to bleed air from your cooling system first and when that is completed, if it still surges, it is probably the valve itself.

My 97’ had an air bleed nipple near the thermostat to aid you in burping the cooling system of air. It is very important that you do NOT have air trapped in the system. Air makes the IAC freak out and will produce the exact symptom you describe. So look into burping your cooling system first…then the valve second. My money is on air in the system…look for a bleed nipple near the T-stat housing…sometimes the bleed is there…other times, not. I’ve never been able to keep track of which have and which do not have the bleed nipple, so look.

Also…if it is air… where did your coolant go? Do you have any coolant leaks? Is your radiator full of coolant up to the top?

If no bleed nipple you need to burp the system the old fashioned way… Hot and cold cycles while topping off the rad and overflow tank. Need a good rad cap and an intact overflow with the hose going to bottom of the overflow tank to allow the hot and cold cycles to burp the system for you…

To Honda Blackbird’s excellent advice I would add: set your heater to Hot. That opens the valve between the engine and the heater core all the way, so all of the cooling system is circulating while you let any air escape.