Base Engine Misfire with Excessive Oil Consumption

WARNING: This page is about a different car, the 2019 Buick Cascada, 2018 Buick Cascada, and 2017 Buick Cascada. However, it is still accessible from the selected car via links, so may be relevant.

Cause	Correction
Worn valves, valve guides, and/or valve stem oil seals	Inspect the spark plugs for oil deposits. Repair or replace 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.