2.8L 2-Bbl.

Turn off all lights and accessories. Place transmission in Neutral or Park. Start and warm engine to normal operating temperature. Set parking brake and block wheels.
Remove Air Charge Temperature (ACT) sensor and adapter from air cleaner tray, keeping wiring harness connected. Remove air cleaner. Disconnect and plug vacuum line at cold weather duct and valve motor.
Turn ignition off. Within 10 seconds, Idle Speed Control (ISC) plunger should move to maximum extension. Disconnect ISC and disconnect and plug EGR vacuum hose. Restart engine and manually open throttle. Set fast idle adjusting screw on highest step of fast idle cam. See Fig 1 .

Fig 1: 2.8L 2-Bbl. Idle Speed Control Adjustment Motorcraft Model 2150A Feedback Carburetor (This Is Not A Normal Tune-Up Procedure)
Adjust fast idle RPM to specification. Open throttle manually to release fast idle cam and allow throttle lever to reset on ISC plunger. Loosen ISC bracket lock screw. Adjust ISC bracket screw to 2000 RPM. Retighten bracket lock screw.
Reconnect ISC. RPM will automatically be adjusted to curb idle. At the same time, manually hold throttle above 1000 RPM, push ISC plunger until it fully retracts and release throttle and quickly unplug connection. Adjust anti-dieseling speed throttle stop screw to specification.
Reconnect ISC and EGR vacuum hose. Shut engine off. Restart engine and verify curb idle speed.

HOT (SLOW) IDLE RPM SPECIFICATIONS