Lack of Power, Sluggishness, or Sponginess. Chevrolet Caprice 1996

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 1996 🢒 Caprice 🢒 Engine 🢒 Engine Controls - 4.3L (Caprice Only) and 5.7L 🢒 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 Symptoms , Important Preliminary Checks Before Starting.

•	Search for bulletins.

•	Check PCM grounds for being clean, tight and in their proper locations. Refer to PCM wiring diagrams in Electrical Diagnosis.

•	Remove and check air filter element for dirt, or for being restricted. Refer to Air Filter Element and Air Cleaner Assembly and replace as necessary.

Fuel System Checks

•	Check for low fuel pressure. Refer to Fuel System Diagnosis .

•	Check for restricted fuel filter. Refer to Fuel System Diagnosis .

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

•	Check items which can cause an engine to run rich (long term fuel trim near -14%). For a Rich condition, refer to DTC P0132 HO2S Circuit High Voltage Bank 1 Sensor 1 and DTC P0152 HO2S Circuit High Voltage Bank 2 Sensor 1 .

•	Check items that can cause an engine to run lean (long term fuel trim near 22%). For a Lean condition, refer to DTC P0131 HO2S Circuit Low Voltage Bank 1 Sensor 1 and DTC P0151 HO2S Circuit Low Voltage Bank 2 Sensor 1 .

Sensor/System Checks

•	Using a scan tool, monitor KS system for excessive spark retard activity. Refer to Knock Sensor (KS) System .

•	Check the EGR system for proper operation.

Ignition System

•	Wetting down the secondary ignition system with water from a spray bottle may help locate damaged or deteriorated components. Look/listen for arcing or misfiring as water is applied.

•	Check for proper ignition voltage output with spark tester J 26792. Refer to Distributor Ignition System for procedure.

•	Remove spark plugs and check for the following:

Wet plugs

Cracks

Wear

-	Improper gap

-	Burned electrodes

-	Heavy deposits

•

An improper spark plug gap will cause a driveability problem. Refer to spark plug gap specification is Section OB. The spark plug gapping should be done using a wire gauge gap tool (J 41319). Refer to Spark Plug Replacement. If spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs. Refer to DTC P0172 Fuel Trim System Rich Bank 1 or DTC P0175 Fuel Trim System Rich Bank 2 to determine the Rich condition or Engine Mechanical for the oil fouling condition.

•	Check for loose ignition coil ground. Refer to Distributor Ignition (DI) System Check .

•	Spark plugs for proper heat range. Refer to Owners Manual or Section OB.

•	Check distributor vent system for being restricted or open. Refer to Distributor Vent System Check .

Engine Mechanical

•	Excessive oil in combustion chamber-Leaking valve seals. Refer to Engine Mechanical.

•	Low cylinder compression. Refer to Engine Mechanical.

•	For incorrect basic engine parts. Inspect the following:

Camshaft

-	Cylinder heads

-	Pistons, etc.

Refer to Engine Mechanical.

Additional Checks

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

-	Inspect exhaust system for damaged or collapsed pipes.

-	Inspect mufflers for heat distress or possible internal failure.

-	For possible plugged Three-Way catalytic converters by comparing exhaust system back pressure on each side of engine. Check back pressure by removing AIR check valves near exhaust manifolds. Refer to Restricted Exhaust System Check and Exhaust System.

•	Check Torque Converter Clutch (TCC) for proper operation. Refer to Transmission Controls.

•	TC system cable adjuster assembly. Loss of performance can result from an improperly adjusted system which could prevent the throttle from attaining WOT. Refer to Antilock Brake System (ABS) and Traction Control System . Also inspect the throttle body and accelerator cables for binding.