Correctly setting your idle speed 1980 - 1988
From the AMC Technical Service Bulletin 12E460
The idle speed may be too low or inconsistent on your 1980 - 1988 Eagle automobile. If this condition exists, the following items must be adjusted to obtain proper engine operation.
Fast Idle Speed
Curb Idle Speed
Sole-Vac Throttle Postioner
Adjustment is as Follows:
1. The engine must be at operating temperature and all electrical accessory switches in the OFF position.
2. Remove the air filter assembly -- make sure to mark where any vacuum hoses connected.
3. Set the parking brake or better yet block the wheels. Shift automatic transmissions to PARK and manual transmissions to the NEUTRAL position.
4. With the ignition switch OFF, connect an ignition timing light to the number 1 spark plug (Figure A) and tachometer to the coil ignition negative terminal (Figure B).
5. Diconnect the 4-in. and 10-in. Hg vacuum switch assebly wire connector located adjacent to the vacuuum switch assembly (Figure C).
6. Disconnect and plug the distributor vacuum advance hose (C) (Figure D).
7. Clean the timing degree scale and mark the notch on the front crankshaft pulley with a white crayon. (Figure E). Start the Engine. Increase the engine speed to 1600 rpm and check the ignition timing. If necessary, adjust the the timing to the specification listed on the Emission Control Label (typically 15 degrees plus or minus 1 degree BTDC and for High Altitude cars 21 degrees plus or minus 1 degree BTDC). You must loosen the distributor hold-down clamp in order to gradually rotate the distributor to achieve the correct timing. Tighten the distributor hold-down clamp and verify timing is correct.
Turn off the engine and remove the timing light. Reconnect the hose to the distributor vacuum mechanism. Reconnect the wire connector to the vacuum switch assmebly.