Auto Repair Q&A



Cooling System










Auto Repair Products

my 92 honda accord lx idles erratically what could be the problem?

1. Verify that the cooling

1. Verify that the cooling system is full of coolant and there is no air in it. 2. Remove the air boot from the throttle body and cover the throttle body with something that will stop the airflow (a hand, tape) with the engine running. With the throttle body covered and no air going into the engine, the engine should stall. If the engine does not stall, look for a vacuum leak. 3. With the engine running, unplug the Idle Air Control (IAC) valve and verify that there is no vacuum on the lower port in the throttle body. If it does not lose vacuum, look for a stuck open IAC valve. 4. Locate the fast idle thermo valve on the front of the intake manifold. It has 2 small coolant lines running to it. Remove the cover and verify that it is sealed off. It should be closed when the engine coolant is over 90 degrees F. If it is not closing, then verify good hot coolant flow to the valve. If the coolant flow is good, then the fast idle valve is faulty. 5. Verify that the base idle screw was not turned way out on the top of the throttle body. If it was, set the base idle and see if the problem still occurs. 6. If the base idle screw is turned all the way in and the fast idle valve is closed and there is still airflow through the upper 11 o'clock port in the throttle body, then check the air boost valve on the end of the intake on the driver's side. It is a metal valve, with a vacuum hose that vents to the air boot. To test it, remove it and tape off the passages on the intake manifold. Verify that the idle speed is correct. To set the base idle, unplug the IAC valve and set the idle speed to 550 RPM with all electrical systems turned off.