Trouble Shooting: Symptoms

NOTE: Some driveability problems may have been corrected by manufacturer with a revised Electrical Control Module (ECM). Check with manufacturer for latest computer application.

Symptom checks can direct the technician to malfunctioning component(s) for further diagnosis. A symptom should lead to a specific component, system test, or adjustment.

Use intermittent test procedures to locate driveability problems that DO NOT occur when the vehicle is being tested. These test procedures should also be used if a soft (intermittent) trouble code was present, but no problem was found during self-diagnostic testing.

NOTE: For specific testing procedures, see SYSTEM/COMPONENT TESTS article. For specifications, see ADJUSTMENTS or SPECIFICATIONS article.

SYMPTOM DIAGNOSIS CHART

Symptom

⁽¹⁾ Possible Cause

Engine Stalls During Idle

Idle Air Control Solenoid Valve, Mass Airflow Sensor, ⁽²⁾ Ignition Parts, ⁽³⁾ Engine Coolant Temp. Sensor, ⁽⁴⁾ Crankshaft Position Sensor, ⁽⁴⁾ Camshaft Position Sensor, EGR Valve, ⁽⁵⁾ Fuel Injection Components

Rough Idle

Idle Air Control Solenoid Valve, Mass Airflow Sensor, ⁽³⁾ Engine Coolant Temp. Sensor, ⁽²⁾ Ignition Parts, ⁽⁶⁾ Air Intake System, ⁽⁵⁾ Fuel Injection Components, Throttle Position Sensor, ⁽⁴⁾ Crankshaft Position Sensor, ⁽⁴⁾ Camshaft Position Sensor, EGR Valve, Oxygen Sensor

Engine Does Not Return To Idle

Idle Air Control Solenoid Valve, Engine Coolant Temp. Sensor, ⁽⁷⁾ Accelerator Cable, Throttle Position Sensor, Mass Airflow Sensor

Poor Acceleration

Mass Airflow Sensor, Throttle Position Sensor, ⁽⁵⁾ Fuel Injection Components, Fuel Pump, Fuel Pump Relay, ⁽³⁾ Engine Coolant Temp. Sensor, ⁽⁴⁾ Crankshaft Position Sensor, ⁽⁴⁾ Camshaft Position Sensor, A/C Switch, A/C Relay, Engine Torque Control Signal Circuit, ⁽²⁾ Ignition Parts

Engine Stalls, Sags Or Hesitates During Acceleration

Mass Airflow Sensor, ⁽³⁾ Engine Coolant Temp. Sensor, ⁽⁴⁾ Crankshaft Position Sensor, ⁽⁴⁾ Camshaft Position Sensor, Purge Control Solenoid Valve, EGR Valve, ⁽⁵⁾ Fuel Injection Components, Throttle Position Sensor, Fuel Pump, Fuel Pump Relay

Surge

Mass Airflow Sensor, ⁽²⁾ Ignition Parts, ⁽³⁾ Engine Coolant Temp. Sensor, ⁽⁴⁾ Crankshaft Position Sensor, ⁽⁴⁾ Camshaft Position Sensor, EGR Valve, ⁽⁵⁾ Fuel Injection Components, Throttle Position Sensor, Fuel Pump, Fuel Pump Relay

Spark Knock

Mass Airflow Sensor, ⁽³⁾ Engine Coolant Temp. Sensor, Knock Sensor, ⁽⁵⁾ Fuel Injection Components, Fuel Pump, Fuel Pump Relay

After-Burn In Exhaust System

Mass Airflow Sensor, ⁽³⁾ Engine Coolant Temp. Sensor, ⁽⁵⁾ Fuel Injection Components, Fuel Pump, Fuel Pump Relay

⁽¹⁾	Check possible causes in order listed.

⁽²⁾	Check ignitor, ignition coil and spark plugs.

⁽³⁾	If symptom occurs only in cold temperatures.

⁽⁴⁾	Ensure component is securely installed.

⁽⁵⁾	Check fuel injectors, fuel pressure regulator and fuel filter.

⁽⁶⁾	Check for air leak(s) in air intake system.

⁽⁷⁾	Adjust accelerator cable.