What are some common engine issues in Audi vehicles?

I've been experiencing some difficulty with my Audi's engine lately. What are some possible causes and solutions for these issues?

Engine oil level may be too low and could be causing the issue. Check the oil levels and top up if necessary.

Spark plugs may be worn out and need to be replaced. It's a relatively easy and inexpensive fix.

Thermostat may be malfunctioning and causing the engine to overheat. Get it checked by a mechanic.