CHECK THESE LAST:

16. CROSS-FIRING BY SPARK PLUGS
Separate spark plug wires; do not run close and parallel.

17. FAULTY FUEL PUMP OR FUEL PRESSURE REGULATOR
Have fuel pump or fuel pressure regulator professionally replaced.

18. EXHAUST MANIFOLD HEAT CONTROL VALVE (HEAT RISER) STUCK OPEN; IF APPARENT DURING ENGINE WARM-UP
Have heat riser professionally serviced.

19. MALADJUSTED OR BINDING CHOKE
Clean choke.
Have automatic choke professionally serviced.

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

21. FAULTY CONDENSER OR BREAKER POINTS
Have condenser or breaker points professionally replaced.

22. FAULTY THROTTLE VALVE OR THROTTLE POSITION SENSOR ON FUEL INJECTION
Have throttle valve or throttle position sensor professionally serviced.