How to diagnose a malfunctioning fuel injector in a Vauxhall Vivaro?

I've noticed that my Vauxhall Vivaro has been struggling with acceleration and has been idling rough. How can I determine if it's a problem with the fuel injector and what steps should I take to fix it?

One possible way to diagnose a malfunctioning fuel injector is to use a fuel pressure gauge to check the pressure in the fuel line. If the pressure is lower than the specified range, it could be a sign of a clogged or faulty injector.

Another method is to use a stethoscope to listen for a clicking sound near the fuel injectors while the engine is running. A lack of clicking could indicate a faulty injector.

If you suspect a specific fuel injector is faulty, you can try swapping it with another one to see if the issue is resolved.