Base Engine Misfire with Abnormal Internal Lower Engine Noises
WARNING: This page is about a different variant/trim than selected.
| Cause | Correction |
|---|---|
| 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. |
| 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 Removal , and Automatic Transmission Flex Plate Installation , or Crankshaft Balancer Removal (LSA)Crankshaft Balancer Removal (LS3 or L99)Crankshaft Balancer Removal (LS7) , and Crankshaft Balancer Installation (LS3, L99, or LSA)Crankshaft Balancer Installation (LS7) . |
| Worn piston rings Oil consumption may or may not cause the engine to misfire. |
|
| 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. |