Base Engine Misfire with Abnormal Internal Lower Engine Noises

WARNING: This page is about a different car, the 2015 Chevrolet Trax and 2015 Buick Encore. However, it is still accessible from the selected car via links, so may be relevant.

Condition	Actions
Abnormalities (server cracking, bumps or missing areas) in the accessory drive belt	Abnormalities in the accessory drive belt and/or components may cause engine RPM variations, noises similar to faulty lower engine and also lead to a misfire condition. A misfire code may be present without an actual misfire condition. Inspect the accessory drive components. Repair or replace all damaged components.
Worn, damaged, or misaligned accessory drive components or excessive pulley runout	A misfire code may be present without an actual misfire condition. Inspect the accessory drive components. Repair or replace all damage components.
Loose and/or damaged crankshaft pulley	A misfire code may be present without an actual misfire condition. Repair or replace all damaged components. Inspect crankshaft pulley and pulley bolt.
Loose torque converter bolts	A misfire code may be present without an actual misfire condition. Inspect torque converter bolts and flywheel. Repair or replace all damaged components.
Loose and/or damaged flywheel	A misfire code may be present without an actual misfire condition. Inspect flywheel and flywheel attaching bolts. Repair or replace all damaged components.
Excessive piston-to-cylinder bore clearance	Perform cylinder leak down and compression tests. Inspect the piston, piston rings and cylinder bore. Repair or replace all damaged components.
Excessive crankshaft thrust bearing clearance	Severely worn thrust surfaces on the crankshaft and/or thrust bearing may permit for and aft movement of the crankshaft and create a misfire code without an actual misfire condition. Inspect the crankshaft end play and crankshaft thrust bearings. Repair or replace all damaged.