How to Adjust the Idle Speed on a 1996 Nissan Pathfinder

A dirty air filter can be the cause of low idle speed.

The idle speed of the 1996 Nissan Pathfinder is adjusted by changing the position of the idle speed adjustment screw. If the idle speed is low, there may be several causes. It could be a dirty air filter or leaks in vacuum hoses or the air intake manifold. Defects in the emissions control, fuel or electrical systems can cause low idle speed. These defects are indicated when the Check Engine light is illumininated. To set the correct idle speed a hand-held tachometer is needed. However, the idle speed is not adjustable if the vehicle has a 3.5L V-6 engine.

Things You'll Need

• Hand-held tachometer
• Wood blocks
• Phillips screwdriver
• Flat-bladed screwdriver

Instructions

1. Remove the air filter. Follow the manufacturer's instructions to set up a hand-held tachometer to read engine speed.

2. Block the wheels to keep the vehicle from moving. Set the parking brake. Place the gearshift in neutral. Start the engine and let it run until it reaches its operating temperature. Turn off any vehicle accessories (heater, air conditioner, lights). Increase the engine speed to about 2000 RPM for two minutes. Next, increase the engine speed briefly to 3000 RPM three times. After two minutes are up, let the engine idle for one minute. Turn off the engine.

3. Disconnect the electrical connector from the throttle position sensor (TPS). The TPS is mounted on the throttle body and has a mechanical link to the throttle. Disconnecting the TPS will cause the Check Engine light to come on. Start the engine and speed it up briefly to 3000 RPM three times. Let the engine idle and read the idle speed on the tachometer. The idle speed should be about 750 RPM. If it's not, it needs to be adjusted.

4. Use a Phillips screwdriver to turn the idle adjustment screw until the idle speed is close to 750 rpm.

5. Turn off the engine. Remove the tachometer. Reconnect the TPS. Install the air filter. Remove the wheel blocks.

6. Clear (turn off) the Check Engine light by finding the power control module (PCM) that is located forward of the center console on the driver's side, behind a trim panel. Remove the trim panel with a Phillips screwdriver. Insert a flat-bladed screwdriver in the mode selector switch with the ignition On and the engine not running. Turn the mode selector switch fully clockwise. Hold it there for two seconds; then turn it one full rotation counterclockwise. Turn the ignition Off. Reinstall the trim panel.

Tips & Warnings

• Correct any problem indicated by a Check Engine light before adjusting the idle speed.

• Do not attempt to turn the idle stop screw located on the throttle body. It is set at the factory and should not be moved.

References

• "Nissan Pick-ups Automotive Repair Manual"; Jeff Kibler and John H. Haynes; 2001

Resources

• "Nissan Pick-ups Automotive Repair Manual"; Jeff Kibler and John H. Haynes; 2001