BASIC DRIVEABILITY PROBLEMS TROUBLESHOOTING

NOTE:

This is GENERAL information. This article is not intended to be specific to any unique situation or individual vehicle configuration. The purpose of this Troubleshooting information is to provide a list of common causes to problem symptoms. For model-specific Troubleshooting, refer to SUBJECT, DIAGNOSTIC, or TESTING articles available in the section(s) you are accessing.

CONDITION & POSSIBLE CAUSE		CORRECTION
Hard Starting
Binding carburetor linkage		Eliminate binding
Binding choke linkage		Eliminate binding
Binding choke piston		Eliminate binding
Restricted choke vacuum		Check vacuum lines for blockage
Worn or dirty needle valve and seat		Clean carburetor, see ENGINE PERFORMANCE
Float sticking		Readjust or replace float see the ENGINE PERFORMANCE section
Incorrect choke adjustment		Reset choke adjustment see ENGINE PERFORMANCE
Defective coil		Replace coil
Improper spark plug gap		Regap spark plugs
Incorrect ignition timing		Reset ignition timing see ENGINE PERFORMANCE
Detonation
Over-advanced ignition timing		Reset ignition timing see ENGINE PERFORMANCE
Defective spark plugs		Replace spark plugs
Fuel lines clogged		Clean fuel lines
EGR system malfunction		Check and repair EGR system
PCV system malfunction		Repair PCV system
Vacuum leaks		Check and repair vacuum system
Loose fan belts		Tighten or replace fan belts, see ENGINE PERFORMANCE
Restricted airflow		Remove restriction
Vacuum advance malfunction		Check distributor operation
Dieseling
Binding carburetor linkage		Eliminate binding
Binding throttle linkage		Eliminate blinding
Binding choke linkage or fast idle cam		Eliminate binding
Defective idle solenoid		Replace idle solenoid see ENGINE PERFORMANCE
Improper base idle speed		Reset idle speed, see see ENGINE PERFORMANCE
Incorrect ignition timing		Reset ignition timing see ENGINE PERFORMANCE
Incorrect idle mixture setting		Reset idle mixture, see ENGINE PERFORMANCE
Faulty Acceleration
Incorrect ignition timing		Reset ignition timing see ENGINE PERFORMANCE
Engine cold and choke too lean		Adjust choke and allow engine to warm-up
Defective spark plugs		Replace spark plugs
Defective coil		Replace coil
Faulty Low Speed Operation
Clogged idle transfer slots		Clean idle transfer slots, see FUEL
Restricted idle air bleeds and passages		Disassemble and clean carburetor, see FUEL
Clogged air cleaner		Replace air filter
Defective spark plugs		Replace spark plugs
Defective ignition wires		Replace ignition wire see ENGINE PERFORMANCE
Defective distributor cap		Replace distributor cap
Faulty High Speed Operation
Incorrect ignition timing		Reset ignition timing see ENGINE PERFORMANCE
Defective distributor centrifugal advance		Replace advance mechanism
Defective distributor vacuum advance		Replace advance unit
Incorrect spark plugs or plug gap		Check gap and/or replace spark plugs
Faulty choke operation		Check choke and repair as required
Clogged vacuum passages		Remove restrictions
Improper size or clogged main jet		Check jet size and clean, see FUEL
Restricted air cleaner		Check filter and replace as necessary
Defective distributor cap, rotor or coil		Replace cap, rotor or coil
Misfire at All Speeds
Defective spark plugs		Replace spark plugs
Defective spark plug wires		Replace spark plug wires
Defective distributor cap, rotor, or coil		Replace cap, rotor, or coil
Cracked or broken vacuum hoses		Replace vacuum hoses
Vacuum leaks		Repair vacuum leaks
Fuel lines clogged		Remove restriction
Hesitation
Cracked or broken vacuum		Replace vacuum hoses hoses
Vacuum leaks		Repair Vacuum leaks
Binding carburetor linkage		Eliminate binding
Binding throttle linkage		Eliminate binding
Binding choke linkage or fast idle cam		Eliminate binding
Improper float setting		Readjust float setting, see FUEL
Cracked or broken ignition wires		Replace ignition wires
Rough Idle, Missing or Stalling
Incorrect curb idle or fast idle speed		Reset idle speed, see see ENGINE PERFORMANCE
Incorrect basic timing		Reset ignition timing see ENGINE PERFORMANCE
Improper idle mixture adjustment		Reset idle mixture, see ENGINE PERFORMANCE
Improper feedback system operation		Check feedback system see ENGINE PERFORMANCE
Incorrect spark plug gap		Reset spark plug gap, see ENGINE PERFORMANCE
Moisture in ignition components		Dry components
Loose or broken ignition wires		Replace ignition wires
Damaged distributor cap or or rotor		Replace distributor cap or rotor
Faulty ignition coil		Replace ignition coil
Fuel filter clogged or worn		Replace fuel filter
Damaged idle mixture screw		Replace idle mixture screw, see FUEL
Improper fast idle cam adjustment		Reset fast idle cam adjustment, see TUNE- see ENGINE PERFORMANCE
Improper EGR valve operation		Replace EGR valve
Faulty PCV valve air flow		Replace PCV valve
Choke binding or improper choke setting		Reset choke or eliminate binding
Vacuum leak		Repair vacuum leak
Improper float bowl fuel level		Reset float adjustment, see FUEL
Clogged air bleed or idle passages		Clean carburetor passages, see FUEL
Clogged or worn air cleaner filter		Replace air filter
Faulty choke vacuum diaphragm		Replace diaphragm, see ENGINE PERFORMANCE
Exhaust manifold heat valve inoperative		Replace heat valve
Improper distributor spark advance		Check distributor operation
Leaking valves or valve components		Check and repair valvetrain
Improper carburetor mounting		Remove and remount carburetor
Excessive play in distributor shaft		Replace distributor
Loose or corroded wiring connections		Repair or replace as required
Engine Surges
Improper PCV valve airflow		Replace PCV valve
Vacuum leaks		Repair vacuum leaks
Clogged air bleeds		Remove restriction
EGR valve malfunction		Replace EGR valve
Restricted air cleaner filter		Replace air filter
Cracked or broken vacuum hoses		Replace vacuum hoses
Cracked or broken ignition wires		Replace ignition wires
Vacuum advance malfunction		Check unit and replace as necessary
Defective or fouled spark plugs		Replace spark plugs
Ping or Spark Knock
Incorrect ignition timing		Reset ignition timing see ENGINE PERFORMANCE
Distributor centrifugal or vacuum advance malfunction		Check operation and replace as necessary
Carburetor setting too lean		Readjust mixture setting, see ENGINE PERFORMANCE
Vacuum leak		Eliminate vacuum leak
EGR valve malfunction		Replace EGR valve
Poor Gasoline Mileage
Cracked or broken vacuum		Replace vacuum hoses hoses
Vacuum leaks		Repair vacuum leaks
Defective ignition wires		Replace wires
Incorrect choke setting		Readjust setting, see ENGINE PERFORMANCE
Defective vacuum advance		Replace vacuum advance
Defective spark plugs		Replace spark plugs
Binding carburetor power piston		Eliminate binding
Dirt in carburetor jets		Clean and/or replace jets
Incorrect float adjustment		Readjust float setting, see FUEL
Defective power valve		Replace power valve, see ENGINE PERFORMANCE
Incorrect idle speed		Readjust idle speed
Engine Stalls
Improper float level		Readjust float level
Leaking needle valve and seat		Replace needle valve and seat
Vacuum leaks		Eliminate vacuum leaks