How to Adjust the Idle on a '95 Ford Mustang

by Lee Sallings

The idle speed in the 1995 Ford Mustang is computer controlled however the computer relies on accurate base idle speed adjustment to be able to control the idle under all conditions. Setting base idle speed, also called minimum air rate, allows the engine to idle near the center of the idle air control valve's travel to provide the widest possible range of idle speeds. The average Mustang enthusiast can make this adjustment in about an hour using basic tools.

Step 1

Start the engine and warm it to operating temperature. In the '95 Mustang, normal operating temperature is indicated when the needle on the dash gauge is between the "R" and the "M" on the word "Normal" stamped on the gauge face. Turn the engine off.

Step 2

Unplug the IAC (Idle Air Control) valve's electrical connector. The IAC in the '95 Mustang is located on the front side of the throttle body attached to the intake manifold on the passenger-side of the engine compartment near the oil filler cap. Restart the engine

Step 3

Remove the black rubber plug that covers the air bleed screw located on top of the throttle body at the base of the boss that the IAC valve is bolted to. Adjust idle speed by turning the air bleed screw using a small Allen wrench until the idle speed is 700 +/- 50 rpm on the Mustang's tachometer.

Step 4

Turn off engine and reinstall the IAC valves electrical connector. Disconnect the negative battery cable from the battery using a 1/2-inch wrench. Wait for 15 minutes and reinstall the negative battery cable. This will reset the on-board of computer and remove any stored trouble codes caused by running the engine with the IAC valve disconnected. Test drive the car to verify that it doesn't stall when at a stop.

Step 5

Test drive the car.

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