Lack of Power, Sluggishness, or Sponginess. Geo Prizm 1997

For 1990-2009 cars

Checks | Action
--- | ---
DEFINITION: The engine delivers less than expected power. There is little or no increase in speed when partially applying the accelerator pedal.

Preliminary Checks

• | Refer to Powertrain Control Module Connector End Views .

• | Refer to Symptoms .

• | Compare the customer's vehicle with a similar unit in order to determine if the customer has an actual problem.

• | Remove the air filter element and check for dirt or restrictions.

• | Check the air inlet duct for any blockage or restrictions.

• | Check the transmission shift pattern and down shift operation.

Fuel System Checks

• | Check for a restricted fuel filter or incorrect fuel pressure

• | Check the fuel injectors. Perform the Fuel Injector Coil Test Procedure and the Fuel Injector Balance Test Procedure. Refer to Fuel Injector Solenoid Coil Test - Engine Coolant Temperature Between 10-35 Degrees C (50-95 Degrees F) and Fuel Injector Balance Test .

• | Check for contaminated fuel.

Ignition System Checks

• | Check for the proper ignition voltage output with a J 26792 or an equivalent.

• | Check for the correct firing order (routing) of the ignition wires.

• | Check the knock sensor and the sensor's circuit shielding. The knock sensor is not diagnosed for excessive activity. A faulty knock sensor or signal interference could cause excessive retard of the ignition timing advance. Observe the Spark parameter on a scan tool and compare with a known good vehicle. A typical value with the transmission in OD at 65 mph is 26-32 degrees.

Exhaust System Checks

• | Check the exhaust system for a possible restriction. Refer to Restricted Exhaust System Check .

• | Inspect the exhaust system for damaged or collapsed pipes. Inspect the muffler for heat distress or a possible internal failure.

Engine Mechanical Check

• | Check for any of the following engine mechanical problems:

- | Low compression

- | Incorrect valve timing

- | Incorrect or worn camshaft

• | Refer to Engine Mechanical.

Additional Checks

• | Check the PCM grounds for being clean, tight, and in their proper locations. Refer to PCM Wiring Diagrams.

• | Check the generator output voltage.