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Base Engine Misfire with Abnormal Internal Lower Engine Noises Hummer H2 I рестайлинг

Mechanical
CauseCorrection
Abnormalities, such as 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 - Accessory .
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 and repair or replace, as required.
Loose or improperly installed engine flex plate or crankshaft balancer A misfire code may be present without an actual misfire condition.Repair or replace the flex plate and/or balancer, as required. Refer to Automatic Transmission Flex Plate Replacement , or Crankshaft Balancer Replacement .
Worn 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 . Inspect the cylinders for a loss of compression. Refer to Engine Compression Test . Perform cylinder leak down and compression testing to determine the cause. Refer to Cylinder Leakage Test . 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.