CHECK THESE LAST:

15. WORN VALVE LIFTERS, VALVE GUIDES, VALVE SPRINGS OR CAMSHAFT
Have valve lifters, valve guides, valve springs or camshaft professionally replaced.

16. FAULTY IGNITION COIL
Have ignition coil professionally replaced.

17. WORN DISTRIBUTOR SHAFT
Have distributor shaft professionally replaced.

18. CARBURETOR ICING; CONFIRMED IF WEATHER IS DAMP AND COOL AND ENGINE RUNS ROUGH ON RESTART
Ensure air intake preheat stove, valve and duct are functioning properly.

19. AIR LEAKS IN INTAKE SYSTEM
Have air leaks professionally repaired.

20. LEAKING CYLINDER HEAD GASKET OR INTAKE MANIFOLD GASKET
Have cylinder head gasket or intake manifold gasket professionally replaced.