Except Distributorless Ignition System (DIS)

Always follow the Emission Control Information Label procedures when adjusting timing.

Set timing at low idle and Before Top Dead Center, unless otherwise specified. Disconnect and plug distributor vacuum hose at distributor.
1981-90 all carburetted with C-3 System, disconnect 4-wire connector at distributor. If "Check Engine" light comes on during procedure, remove ECM fuse to clear.
1982-86 1.8L (112) FI, 2.5L (151) engines, ground diagnostic connector.
1983-86 2.0L (122) FI, 2.8L (173) FI, disconnect EST bypass connector (tan/black wire).
All W/O distributor not adjustable.