How to troubleshoot a faulty engine in a Vauxhall Insignia?

My Vauxhall Insignia's engine seems to be malfunctioning. It's making a strange noise and it doesn't accelerate smoothly. I'm worried about driving it. Can someone help me identify and fix the issue?

First, I would suggest checking the engine oil level and color. If it's low or has a milky appearance, it could be a sign of a leak or a blown head gasket. Otherwise, it could indicate a problem with the fuel system or spark plugs. I recommend taking the car to a certified mechanic for a diagnostic test.

Another possibility is a faulty oxygen sensor. This can cause the engine to run rough and decrease fuel efficiency. It's a relatively easy and inexpensive fix that you can do yourself, but if you're not comfortable working on your car, a mechanic can do it for you.

If you notice the engine stalling or misfiring, it could be a clogged fuel filter. This is a common issue in older cars and it's important to replace the filter regularly to prevent damage to the engine. You can check your owner's manual for the recommended service interval.