The engine doesn't start up very easily and will often not start at all. When it is running it can cut out completely without warning.
The dashboard warning light showing on this page (or one very similar, sometimes a slightly different shape or colour) has appeared on the dashboard and doesn't go off when the car is running.
When the engine is running it does sound like it would normally, it can sound like it's struggling to keep running or produce strange noises that sound like it's not running in time with itself.
The engine sounds like it's not running correctly, the engine sounds rough as if it's not running in time.
The engine doesn't sound normal, it can sound like it's struggling to keep running or out of time. The engine note produced by the engine can also sound very different, it's often a deeper, more bass heavy sound that it is normally.