How to troubleshoot a malfunctioning BWM engine?

I have a BWM car and recently the engine started making odd noises and the performance has decreased. What steps should I take to troubleshoot and fix the issue?

First, check the engine oil level and quality. Low or dirty oil can cause the engine to produce strange noises and decrease performance. Make sure to change the oil regularly according to your manufacturer's guidelines.

Next, inspect the spark plugs and wires. Worn or damaged spark plugs can cause misfiring and affect the engine's performance. Replace them if needed.