Surges/Chuggles. Cadillac Seville 2004

For 1990-2009 cars only

Makes 🢒 Cadillac 🢒 2004 🢒 Seville 🢒 Engine 🢒 Engine Controls - 4.6L 🢒 Surges/Chuggles

Inspection/Test

Action

DEFINITION: Engine power variation under steady throttle or cruise. Feels like the vehicle speeds up and slows down with no change in the accelerator pedal.

Preliminary

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

•	Search for bulletins.

Be sure that the driver understands the transmission torque converter clutch (TCC), and A/C compressor operation as explained in the owners manual. Inform the customer how the TCC and the A/C system operate.

Sensor/System

•	Inspect the heated oxygen sensors (HO2S)s. The HO2Ss should respond quickly to different throttle positions. If they do not, check the HO2S for the following conditions:

-	Contaminants from the fuel

-	Improper use of RTV

-	The sensors may have a white powdery coating. This will result in a high but false signal voltage (rich exhaust indicated). The powertrain control module (PCM) will reduce the amount of fuel delivered to the engine causing a severe driveability condition.

•	Inspect the mass air flow (MAF) sensor and intake air system for proper connections.

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

Fuel System

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

•	Test 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 HO2S connector.

•	Engine oil contaminated by fuel.

•	An 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 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 mass air flow (MAF) sensor.

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

•	Vacuum hoses for splits, kinks and proper connections.

Ignition System

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

•	Inspect for damaged ignition coils within the ignition coil module assemblies.

•	Inspect for damaged or misaligned spark plug boots.

•	Inspect for a missing or damaged ignition module ground spring.

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

Additional

•	Inspect the vacuum hoses for splits, kinks, and improper connections or routing.

•	Inspect torque converter clutch (TCC) operation. Refer to Torque Converter Diagnosis in Automatic Transaxle.

•	Inspect for a restrictive exhaust system. Refer to Restricted Exhaust .