Lack of Power, Sluggishness, or Sponginess. Pontiac Grand Prix 2001

For 1990-2009 cars only

Makes 🢒 Pontiac 🢒 2001 🢒 Grand Prix 🢒 Engine 🢒 Engine Electrical 🢒 Lack of Power, Sluggishness, or Sponginess

Lack of Power, Sluggish or Spongy

Checks

Action

DEFINITION: Engine delivers less than expected power. Little or no increase in speed when the accelerator pedal is pushed down part way.

Preliminary Checks

•	Refer to Diagnostic System Check - Engine Controls .

•	Refer to Important Preliminary Checks.

•	Refer to Visual/Physical Checks.

•	Search for bulletins.

Fuel System Checks

•	Test the system fuel pressure. Refer to Fuel System Diagnosis .

•	Test the fuel injectors using the following tests:

-	Refer to Fuel Injector Solenoid Coil Test .

-	Refer to Fuel Injector Balance Test with Tech 2 .

•	Test for contaminated fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .

•	Inspect items which can cause an engine to run rich (long term fuel trim is significantly in the negative range). Refer to Diagnostic Aids for DTC P0172 .

•	Inspect items that can cause an engine to run lean (long term fuel trim is significantly in the positive range). Refer to Diagnostic Aids for DTC P0171 .

Sensor/System

•	Use a scan tool in order to inspect for excessive spark retard activity. Refer to Knock Sensor (KS) System Description .

•	Test the exhaust gas recirculation (EGR) system for proper operation. Refer to Exhaust Gas Recirculation (EGR) System Description .

•	Inspect for a restricted air intake system. Refer to Air Intake System Description .

Ignition System

•	Test for proper ignition voltage output using the following steps:

-	Clip the J 26792 spark tester to engine ground.

-	Connect one end of a spark plug wire to the J 26792 . Connect the other end of the spark plug wire to the coil being tested.

-	Connect another spark plug wire between the remaining tower of the coil being tested and ground.

-	Crank the engine while observing the J 26792 . A crisp blue spark should be observed.

-	Repeat the above steps for each coil.

•	If spark is not present at the coils, test for the following conditions:

-	Coils--Cracks, carbon tracking/arcing, or a secondary resistance value outside the specified range

Coil Resistance
5,000-8,000 ohms (5K-8K ohms)

-	Spark plug wires--Signs of arcing/cross firing, cracks, carbon tracking, plug boot damage, pinched, improper routing, or a resistance value outside the specified range

Spark Plug Wire Resistance
600 ohms per foot

Important: Spraying the secondary ignition wires with a light mist of water may help locate an intermittent condition. Ignition components will arc to ground when a secondary component is faulty.

-	Defective module

-	Ignition system wiring--Loose ignition module feed or ground connection, or damaged system wiring

•	Remove spark plugs and inspect for the following:

-	Fouled plugs

Cracks

Wear

-	Improper gap

-	Burned or damaged electrodes

-	Improper heat range or reach

•	If spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs.

Engine Mechanical

•	Excess oil in combustion chamber--Inspect for leaking valve seals. Refer to Oil Consumption Diagnosis in Engine Mechanical 3.8L.

•	Low cylinder compression--Refer to Engine Compression Test in Engine Mechanical 3.8L.

•	Inspect for incorrect engine parts, such as the following basic components:

Camshaft

-	Cylinder heads

-	Pistons, etc.

Refer to Symptoms - Engine Mechanical in Engine Mechanical 3.8L.

Additional Checks

•	Inspect the exhaust system for possible restrictions. Inspect for the following:

-	Inspect the exhaust system for damaged or collapsed pipes.

-	Inspect the mufflers for heat distress or possible internal failure.

-	For a possible plugged 3-way catalytic converter--Refer to Restricted Exhaust in Engine Exhaust.

•	Check for proper torque converter clutch (TCC) operation. Refer to Torque Converter Diagnosis in Automatic Transaxle -4T65-E.