Sylphy uneven idling error

I had something similar happen with my Sylphy. Those uneven idles are a pain! Check your transmission mount and the rubber mounts in general. A failed mount can cause all sorts of weird vibrations and error codes. How are the motor mounts looking? Could be mount wear, it all adds up.

When you had the problem, were the symptoms identical? Like, exactly the same? Or were there differences? Did yours also throw an error code or just vibrate like crazy?

Yeah, the symptoms were pretty much spot on - rough idling for sure, and the error code was definitely there. I'd get it checked at a workshop; they can diagnose it properly. Could be a defective cable or plug connection as you mentioned which is pretty hard to spot yourself.

I got it checked out. Turns out it was the engine mount, and the cable connection was indeed defective, just like I suspected. 95€ later, and it's running smooth as butter. Appreciate the help!