Fuel Delivery and Air Induction: Adjustments

Perform adjustments with automatic transmission in park, manual transmission in neutral, unless otherwise noted.
1. Run engine at 3,000 RPM and adjust lean mixture screw, as needed to obtain a dwell reading of 35°. If reading is too low, turn screw counterclockwise; if reading is too high, turn screw clockwise. Make adjustments in small increments, allowing time between adjustments for engine and dwell meter to stabilize.
2. Return engine to idle.
3. Adjust idle mixture screw, as needed, to obtain a dwell reading of 25°, with engine cooling fan off. If reading is too low, turn screw counterclockwise; if reading is too high, turn screw clockwise. Make adjustments in small increments, allowing time between adjustments for engine and dwell meter to stabilize. Make final check with mixture adjusting tool removed.
4. With engine cooling fan off, disconnect wiring harness connector to MC solenoid. Engine speed should change at least 50 RPM. If not check for restriction, leak, etc. in idle air bleed circuit.
5. Run engine at 3,000 RPM while observing dwell meter. Meter should indicate fluctuating dwell with an average reading of 35°. If reading is not within specifications, repeat steps 1-5.
6. Reinstall vent screen stack, reconnect vacuum hoses to proper fittings, and reinstall air cleaner. Check and adjust curb idle speed to specifications, as needed.