What is the most common cause of engine misfires in a Vauxhall Insignia?

I recently purchased a used Vauxhall Insignia and I've been experiencing engine misfires. I've changed the spark plugs and ignition coils but the issue still persists. Any suggestions on what could be causing this?

The most common cause of engine misfires in a Vauxhall Insignia is a faulty fuel injector. I would recommend getting them checked and possibly replaced if necessary by a certified mechanic.

Another potential cause of engine misfires in a Vauxhall Insignia is a clogged air filter. Make sure to replace your air filter regularly to prevent this issue.

Check your fuel pressure and make sure it is within the manufacturer's recommended range. If it's too high or too low, it can cause engine misfires.

It's possible that the misfires are caused by a problem with the electrical system. I would suggest getting the wiring and connections checked by a professional.

If the engine misfires are accompanied by a rough idle and difficulty starting the car, it could be a sign of a worn out timing belt. Have it inspected and replaced if needed.