2003 Ford Explorer intermittent missing

JOHNSON4824

MEMBER
2003 FORD EXPLORER
6 CYL
AWD
AUTOMATIC
102,000 MILES

I am having a problem while my truck idles at a light and only when it is in gear, the engine will sorta choke and the rpms will drop down to almost stall then it will come right back, this happens about every 10 seconds some time more or less. It only stalled once on me. When I accelerate it is smooth no loss of power at all or miss. Over the summer I replaced the spark plugs which were very old, as I am the second owner I checked all the wires to make sure they were intact and not arcing anywhere and nothing. I also removed the air filter box to clean it out so I unplugged the sensor on it maybe I hurt it when I did this Im not sure but I need help.

1 Reply

DAVE H

MECHANIC
13,383 POSTS

IDLE CONTROL SYSTEM
Idle Air Control Valve Assembly
Idle Air Control (IAC) valve assembly is used to control idle speed and provide a dashpot function. IAC valve assembly meters inlet air around the throttle plate through a by-pass within the IAC valve assembly and throttle body. See Fig. 46 -Fig. 48 .
The Powertrain Control Module (PCM) determines desired idle speed or air by-pass and signals the IAC valve assembly through specified duty cycle. The IAC solenoid is built into IAC valve assembly. IAC solenoid responds by positioning the IAC valve to control amount of air by-passed. PCM monitors engine speed and adjusts IAC duty cycle to achieve desired RPM. IAC valve assembly is not adjustable and cannot be cleaned.
On applications with air assisted injectors, IAC valve supplies a small jet of air into path of fuel injectors, creating an increase in fuel atomization at low speed and light load conditions.

IDLE AIR CONTROL VALVE
NOTE:Numbers in parenthesis refer to numbers in illustration.

Removal & Installation (4.0L)
Disconnect negative battery cable. Disconnect Idle Air Control (IAC) valve connector (1). See Fig. 20 . Remove wire harness retainer (2) and splash shield spacer nut (3). Remove IAC valve bolts (4) and remove IAC valve (5). To install, reverse removal procedure. Tighten bolts to specification. See TORQUE SPECIFICATIONS .
Fig. 20: Removing IAC Valve (4.0L)
Courtesy of FORD MOTOR CO.

Removal & Installation (4.6L)
Disconnect negative battery cable. Disconnect air inlet tube assembly from Idle Air Control (IAC) valve (1). See Fig. 21 . Disconnect IAC valve connector (2). Remove IAC valve bolts (3) and remove IAC valve (4). Remove IAC valve gasket (5). To install, reverse removal procedure. Tighten bolts to specification. See TORQUE SPECIFICATIONS .
Fig. 21: Removing IAC Valve (4.6L)
Courtesy of FORD MOTOR CO.