How do I check for faulty spark plugs in my Audi A4?

I have been having some issues with my Audi A4's performance lately and I suspect that it may be due to faulty spark plugs. How can I check if this is the case?

First of all, make sure to disconnect the spark plug ignition cables before checking for faults. Next, visually inspect each spark plug for any signs of damage such as cracks or corrosion. Another way to check is by using a spark plug tester tool to see if it is producing a spark. Lastly, if you have access to a diagnostic scanner, you can check for any error codes related to the spark plugs. As always, if you are unsure or uncomfortable performing these checks, it is best to take your Audi to a certified mechanic.