2002 Ford Explorer Stalls

Hi, when stopping at a light the car stalls. I have replaced the idle control valve, fuel pump, had the transition checked, checked for air leaks. No luck. The idle RPM appears low at 600. Alldata says that the idle is set at 890 RPM. Any ideas on what else I can check or how to raise the idle RPM.


The way I understand it the PCM controls idle speed with the idle air control valve. You can not increase the idle speed without a custom tune. Did you check the idle air control circiut? There may be a steady input voltage and varialble output resistance to control the valve or the input voltage might vary. Either way, this is probably the next step.

Thanks for the reply. I believe that Ford uses a PWM signal to drive the Idle control valve. Does anyone know the PWM duty cycle for normal idle?

Have you checked the air passage on both sides of the IAC?

The following is for a '99 4.6l in a different vehicle. I hope it is close:

Is it any different if you unplug the IAC? if it does not change, first check the circuit between the pwr and gnd circuits in the IAC wires between the IAC and PCM connectors for shorts to ground and power and for open circuit.

IAC valve resistance 6-13 ohms
IAC either pin to case > 10 Kohms

Normal operating temp, accessories off and at closed throttle the duty cycle should be between 22 and 45%. Put a shim under the stop to keep it running if you need to for KOER.

VPWR voltage at the IAC connector is supposed to be 10.5 V (KEOR)

Thanks for the info! I will put an OScope on it this weekend. I called a local Ford dealer today and they told me that the RPM is 550 to 650 and 620 is normal. Does anyone think that the lock up torque converter is not unlocking when I come to a stop?

That is certainly possible. I think you can unplug the connector that controls the lock-up to disable it. That would certainly allow you to diagnose the problem.

Thanks, I will also try doing that. The only problem is that this only happens every two weeks.