Lack of Power, Sluggishness, or Sponginess. Cadillac DeVille 2005

For 1990-2009 cars only

Makes 🢒 Cadillac 🢒 2005 🢒 DeVille 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 Lack of Power, Sluggishness, or Sponginess

Inspection/Test

Action

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

Preliminary

•	Refer to Important Preliminary Checks Before Starting in Symptoms - Engine Controls .

•	Search for bulletins.

Sensor/System

•	Inspect the knock system (KS) for excessive spark retard.

•	Inspect the exhaust gas recirculation (EGR) system for proper operation.

•	Inspect for a dirty or damaged air cleaner element.

•	Inspect for collapsed, or damaged intake air ducting.

Fuel System

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

•	Test the fuel injectors. Refer to the following:

-	Fuel Injector Solenoid Coil Test

-	Fuel Injector Balance Test with Tech 2 or Fuel Injector Balance Test with Special Tool

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

Inspect the following that may cause the engine to run rich:

Notice: Refer to Heated Oxygen and Oxygen Sensor Notice in the Preface section.

•	Any water intrusion in the heated oxygen sensor (HO2S) connector

•	Engine oil contaminated by fuel

•	An evaporative emission (EVAP) canister purge condition

•	Incorrect fuel pressure--Refer to Fuel System Diagnosis .

•	A leaking fuel pressure regulator

•	Any rich fuel injectors--Refer to Fuel Injector Balance Test with Tech 2 and Fuel Injector Balance Test with Special Tool .

•	Inaccurate mass air flow (MAF) sensor

•	Blockage on the inlet screen of the MAF sensor

•	Vacuum hoses for splits, kinks and proper connections

•	The air intake duct for being collapsed or restricted

•	The air filter for being dirty or restricted--Refer to Air Cleaner Element Replacement

Inspect the following that may cause the engine to run lean:

Notice: Refer to Heated Oxygen and Oxygen Sensor Notice in the Preface section.

•	Any water intrusion into the HO2S connector

•	An exhaust leak between the HO2S and the engine--Refer to Exhaust Leakage in Engine Exhaust.

•	Any vacuum leaks

•	Incorrect fuel pressure--Refer to Fuel System Diagnosis .

•	Any lean fuel injectors--Refer to Fuel Injector Balance Test with Tech 2 and Fuel Injector Balance Test with Special Tool .

•	An inaccurate MAF sensor

•	Fuel contamination--Refer to Alcohol/Contaminants-in-Fuel Diagnosis .

•	Vacuum hoses for splits, kinks and proper connections

Ignition System

•	Inspect for proper connections at each ignition module assembly.

•	Test for proper ignition voltage output using the J 26792 Spark Tester .

•	Inspect the ignition coils for cracks or damage.

•	Inspect for a missing or damaged ignition module assembly grounding spring.

•	Inspect for damaged or misaligned spark plug boots.

•	Inspect the spark plugs. Refer to Spark Plug Inspection .

Engine Mechanical

•	Inspect for excessive oil in the combustion chamber-leaking valve seals. Refer to Oil Consumption Diagnosis in Engine Mechanical - 4.6L.

•	Inspect for low cylinder compression. Refer to Engine Compression Test in Engine Mechanical - 4.6L.

•	Inspect for incorrect basic engine parts. Inspect the following:

Camshafts

-	Cylinder heads

-	Pistons, etc.

Additional

•	Inspect the exhaust system for possible restrictions. Refer to Restricted Exhaust .

•	Inspect for proper torque converter clutch (TCC) operation. Refer to Torque Converter Diagnosis in Automatic Transaxle - 4T80-E.

•	Inspect for conditions that cause the engine torque management system to reduce engine power.