Base Engine Misfire with Abnormal Internal Lower Engine Noises. Cadillac CTS

For 1990-2009 cars only

Makes 🢒 Cadillac 🢒 2003 🢒 CTS - RHD 🢒 Engine 🢒 Engine Mechanical - 2.6L and 3.2L 🢒 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 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. Refer to Drive Belt Replacement .

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 engine flywheel and/or crankshaft balancer as required. Refer to Engine Flywheel Replacement or Crankshaft Balancer Replacement .

Worn or Broken Piston Rings

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

•	Inspect the spark plugs for oil deposits. Refer to Spark Plug Inspection in Engine Controls.

•	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 DTC without an actual misfire condition.

Replace the crankshaft and bearings as required.