Idle Speed for 2.8 Factory Carb


Aug 7, 2007
Reaction score
Northern California
Vehicle Year
1995, 2001, 200
Make / Model
Engine Size
Idle Speed Setting Procedure
2.8 Liter Engine w/2150A F13 Carburetor and DC Motor Idle Speed Control Instructions (Factory Stock)

If EEC-IV engine curb idle rpm is not at specified speed after performing this procedure, it will be necessary to perform the appropriate 2.8L FB EEC-IV diagnostic procedure.

1. Warm up engine until operating temperature is reached. Set parking brake and block wheels and turn Off all accessories.

2. Remove ACT sensor and adapter from air cleaner tray (remove retainer clip inside tray) and leave it connected to wiring harness. Remove air cleaner, disconnect and plug the vacuum line at bottom of air cleaner if present.

3. Turn engine Off. Idle Speed Control (ISC) plunger will move to maximum extension (verify visually that plunger moves out within 10 seconds of key Off, if possible).

4. Disconnect idle speed control. Disconnect and plug EGR vacuum hose.

5. With the engine running, manually open throttle and set fast idle adjusting screw on high cam.
6. Adjust fast idle RPM to specification.

7. Open throttle manually to release fast idle cam, allowing throttle lever to rest on ISC plunger.

8. 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).

10. Simultaneously:
o Manually hold throttle above 1000 RPM. Push ISC plunger until it retracts fully. After plunger retracts, release throttle and quickly unplug connection.

11. Adjust anti-dieseling speed throttle stop screw to specification (anti-dieseling speed and NOT curb idle speed).
* 750 RPM for manual transmission in Neutral. * 650 RPM for automatic transmission in Drive. NOTE: If throttle stop screw does not have a screwdriver slot and requires adjustment-using pliers, grasp the screw threads and turn screw until it is removed from the carburetor. Install a new throttle stop screw and adjust to specification.

12. Reconnect ISC and EGR vacuum hose.

13. Shut engine Off.
14. Restart engine. Verify curb idle speed is within specification.

This has been asked before, but it was too much for me to type.