Base Engine Misfire with Abnormal Internal Lower Engine Noises. Pontiac G3 2009

For 1990-2009 cars only

Makes 🢒 Pontiac 🢒 2009 🢒 G3 🢒 Diagnostic Navigation 🢒 Vehicle Diagnostic Information 🢒 Base Engine Misfire with Abnormal Internal Lower Engine Noises

Cause

Correction

Abnormalities, severe cracking, bumps or missing areas in the accessory drive belt

Abnormalities in the accessory drive system and/or components may cause engine revolutions per minute (RPM) variations, noises similar to a faulty lower engine, and also lead to a misfire condition. A misfire code may be present without an actual misfire condition.

Replace the drive belt.

Worn, damaged, or mis-aligned accessory drive components or excessive pulley runout

A misfire code may be present without an actual misfire condition.

Inspect the components, repair or replace as required.

Loose or improperly installed engine flywheel or crankshaft balancer

A misfire code may be present without an actual misfire condition.

Repair or replace the flywheel and/or balancer as required.

Worn piston rings

Oil consumption may or may not cause the engine to misfire.

•	Inspect the spark plugs for oil deposits.

•	Inspect the cylinders for a loss of compression. Refer to Engine Compression Test.

•	Perform cylinder leak down and compression testing to determine the cause.

•	Repair or replace as required.

Worn crankshaft thrust bearings

Severely worn thrust surfaces on the crankshaft and/or thrust bearing may permit fore and aft movement of the crankshaft, and create a diagnostic trouble code (DTC) without an actual misfire condition.

Replace the crankshaft and bearings as required.