How to troubleshoot a rough idle on a Ford Fiesta?

I have been experiencing a rough idle on my Ford Fiesta and it's causing the car to shake. What could be the possible causes and how can I fix this issue?

A rough idle can be caused by a variety of issues such as dirty spark plugs, a vacuum leak, or a malfunctioning idle air control valve. I would recommend checking these components and cleaning or replacing them if necessary.

Another potential cause of a rough idle in a Ford Fiesta is a clogged fuel filter. This can restrict the flow of fuel to the engine and cause it to run poorly. I suggest replacing the fuel filter if it hasn't been changed recently.

It's also a good idea to have the engine's computer scanned for any error codes. This can help pinpoint the specific issue that is causing the rough idle and provide a more targeted solution.