Additional Symptoms Tests

WARNING: This page is about a different variant/trim than selected.

Detonation/Spark Knock

Test the engine for an overheating condition. Refer to Symptoms - Engine Cooling
Inspect for excessive carbon buildup in the combustion chambers. Clean the chambers with Top Engine Cleaner, if necessary. Follow the instructions on the can.

Fuel Odor

Inspect for a saturated EVAP canister. Refer to Evaporative Emission Control System Description .
Inspect for a condition with the internal components of the fuel tank assembly. Refer to Fuel System Description .

Hard Start

Observe the scan tool Throttle Body Idle Airflow Compensation parameter. A value greater than 90% may indicate an excessive accumulation of deposits in the throttle bore. Inspect the throttle body and bore and clean, if necessary. Refer to Throttle Body Inspection and Cleaning .
Test the engine coolant temperature (ECT) sensor. Compare the ECT sensor value to the intake air temperature (IAT) sensor value on a cold engine. The ECT and IAT sensor values should be within approximately 3°C (5°F). If the ECT sensor is out of range with the IAT sensor, test the resistance of the ECT sensor. Refer to Temperature Versus Resistance (ECT) for resistance specifications. Replace the ECT sensor if the resistance is not within specification. If the sensor is within the specification, test the ECT circuits for a high resistance.
Test the fuel pump relay operation. The fuel pump should turn ON for 2 s when the ignition is turned ON. Refer to Fuel Pump Electrical Circuit Diagnosis .

Hesitation, Sag, Stumble

Test the fuel pressure. Refer to Fuel System Diagnosis .
Test the manifold absolute pressure (MAP) sensor. Refer to DTC P0106 (LUW) .
Test the generator. Refer to Symptoms - Engine Electrical . Repair the charging system if the generator output voltage is less than 9 V or more than 16 V.

Poor Fuel Economy

Inspect for heavy loads being carried or towed
Inspect for acceleration rate too much or too often
Observe the scan tool Throttle Body Idle Airflow Compensation parameter. A value greater than 90% may indicate an excessive accumulation of deposits in the throttle bore. Inspect the throttle body and bore and clean, if necessary. Refer to Throttle Body Inspection and Cleaning .
Inspect the brake system for brake drag.

Poor Fuel Fill Quality

For more information, refer to the following:

Rough, Unstable, or Incorrect Idle and Stalling

Observe the scan tool Throttle Body Idle Airflow Compensation parameter. A value greater than 90% may indicate an excessive accumulation of deposits in the throttle bore. Inspect the throttle body and bore and clean, if necessary. Refer to Throttle Body Inspection and Cleaning .
Inspect the engine mounts. Refer to Engine Mount Inspection .
Inspect the intake and exhaust manifolds for casting flash.
An excessively high idle may be due to the floor mat interfering with the accelerator pedal. With this condition present, it may not be possible to shift the transmission into gear. Inspect the accelerator pedal for binding and verify that the floor mat is not interfering with the accelerator pedal movement.

Surges/Chuggles

Verify that each injector harness is connected to the correct injector.
Inspect for slow responding heated oxygen sensors (HO2S). The heated oxygen sensors should respond quickly to a change in throttle position. If the heated oxygen sensors do not respond to different throttle positions, inspect for contamination from fuel, silicon, or the incorrect use of RTV sealant. The sensors may have a white powdery coating and result in a high, but false, signal voltage, which gives a rich exhaust indication. The engine control module reduces the amount of fuel delivered to the engine, causing a drivability condition. Refer to DTC P0133, P013A, P013B, P013E, P013F, P015A, P015B, P2270, or P2271 (LUW) for additional information.