Cuts Out, Misses. Cadillac DeVille 2005

For 1990-2009 cars only

Makes 🢒 Cadillac 🢒 2005 🢒 DeVille 🢒 Engine 🢒 Engine Controls - 4.6L 🢒 Cuts Out, Misses

Inspection/Test

Action

DEFINITION: Steady pulsation or jerking that follows engine speed, usually more pronounced as the engine load increases.

Preliminary

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

•	Search for bulletins.

•	Inspect the intake air system for the following conditions:

-	Dirty or damaged air filter element

-	Restrictions

-	Damaged or disconnected intake air ducting

Sensor/System

•	Inspect mass air flow (MAF) sensor and connections.

•

Test the engine coolant temperature (ECT) sensor for being shifted in value. Connect the scan tool and compare the engine coolant temperature (IAT) with the intake air temperature on a cold engine. The ECT and IAT should be within ±3°C (5°F) of each other. Check the resistance of the ECT sensor if the temperature is out of range with the IAT sensor. Refer to Temperature Versus Resistance for specifications.

•	Inspect throttle position (TP) sensor and connections. Refer to DTC P0121 .

•	Inspect for throttle body tampering, excessive deposits, or damage.

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

Fuel System

•	Test fuel pressure. Refer to Fuel System Diagnosis .

•	Test fuel injectors and related wiring. Refer to Fuel Injector Solenoid Coil Test , Fuel Injector Balance Test with Special Tool and Fuel Injector Balance Test with Tech 2 .

•	Inspect for fuel in the fuel pressure regulator.

•	Test for contaminants in the 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 crankshaft position (CKP) sensor A and B for proper operation.

•	Inspect the ignition control (IC) circuits at each ignition module assembly for poor connections, damage, misrouting.

•	Inspect the ignition coils for damage.

•	Inspect the spark plug boots for misalignment, and damage.

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

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

Engine Cooling

•	Inspect the engine coolant level for being too low. Refer to Loss of Coolant in Engine Cooling.

•	Inspect for an incorrect, damaged, or malfunctioning thermostat. Refer to Thermostat Diagnosis in Engine Cooling.

Engine Mechanical

•	Inspect the following:

-	Engine compression--Refer to Engine Compression Test in Engine Mechanical

-	Sticking or leaking valves

-	Worn camshaft lobes

-	Valve timing

-	Worn rocker arms-- Refer to Valve Rocker Arms Cleaning and Inspection in Engine Mechanical.

-	Broken valve springs--Refer to Valve Spring Inspection and Measurement in Engine Mechanical.

-	Excessive oil in the combustion chamber, leaking valve seals.

•	Inspect the following for incorrect basic engine parts:

Camshaft

-	Cylinder heads

-	Pistons, etc.

Additional

•	Inspect the vacuum hoses for splits, kinks, proper routing and connections, and/or damage. Refer to the Vehicle Emission Control Information label.

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

•	An engine miss condition can be caused by electromagnetic interference (EMI). EMI can usually be detected by monitoring the engine RPM with a scan tool. A sudden increase in RPM with little change in the actual engine RPM, indicates EMI is present.