!993 Accord Has Erratic idle

My Accord has a crazy idle, it idles between 1500 and 2500 rpms, but after its put in drive it drops to about 1100. Im thinking idle control valve, but I want a second opinion.

Before you replace that part ( it is expensive) check your vacuum system for leaks and proper routing. Also replace your thermostat to rule it out as causing the problem. It is a cheap part and it is very important in determing how the car will run depending on the temp it is at. After you do this, follow the procedure in a haynes manual for adjusting the idle speed. I had the erratic idle in my 91, it bounced from 1100 to 2000, and after these steps i eliminated the problem with out spending much dough.

My Accord has a crazy idle, it idles between 1500 and 2500 rpms, but after its put in drive it drops to about 1100. Im thinking idle control valve, but I want a second opinion.


check the fast idle thermo valve unscrew cover and use a pair
of needle nose plyers and tighten down that helped my 92 acc.

The first thing to check is the coolant level. If this is low it will not circulate through the thermal valve. If the coolant is full and there is no air in the system, you need to check for coolant flow through the thermal valve. The valve is located on the front of the intake manifold and is the valve towards the drivers side. With the engine warm, check the temperature of both hoses at the thermal valve and the idle control motor (next to thermal valve). If the coolant is flowing normally both hoses will be hot. Once you have established proper flow, then you can go further with diagnosing the thermal valve and idle control motor. Normally you will find the problem is with flow or the lack of flow.

check for vacuum leaks, o2 sensors and spark plugs...