What causes a loud knocking noise in my Vauxhall Vivaro's engine?

I have noticed a loud knocking noise coming from the engine of my Vauxhall Vivaro. It seems to happen more frequently when accelerating or decelerating. What could be causing this and how can I fix it?

The loud knocking noise in your Vauxhall Vivaro's engine could be due to several things. It could be a sign of low oil levels, worn out engine bearings, or a faulty fuel injector. It is important to get it checked by a mechanic as soon as possible to avoid further damage to your engine.

My Vauxhall Vivaro had a similar issue and it turned out to be a loose exhaust pipe causing the knocking noise. It is worth checking all the connections and tightening them if needed.

I had the same problem with my Vauxhall Vivaro and it was because of a faulty spark plug. I replaced it and the knocking noise was gone. It is a cheap and easy fix, so I would recommend checking your spark plugs.