Vw lupo sdi vibrating on idle

engine mounts

which engine.??? never post lacking engine ,here is why.
1.3 L G13B I4
1.5 L G15A I4
1.6 L G16B I4
1.8 L J18A I4
1.8 L BP-ZE I4
1.9 L XUD9 diesel I4

Ill answer in the generic and for GAS engines. only.
that is illegal RPM, the ECU regulates it to 800 all the time
that means the ECU can not regulate the RPM now, for many reasons.
and sure it vibrates too low, that is normal for all 4cylinders to do that.
no bad engine mounts never lower RPM to 600, ever.
they dont control idle speed at all.
the #1 reason for most cars to idle too low are:
1: EGR leaks, (clean it)
2: ISC stuck closed (electric idle speed acututor dirty) clean it.
3: gross misfiring , caused by bad spark or bad fuel mix.
4: low compression on 1 or more cylinders (real low) Do compression test at WOT. throttle.

have you checked the motor mounts? A bad motor mount will shake rattle and roll.

hello,good day,seem you have problem on ignition or fuel system,maybe one spark plug or nozzle need replacement,or better to send your car to a dealer for proper diagnose,ty

Sounds like one of your engine or gearbox mountings are faulty or broken, Check them and try moving the motor with a long bar, if they are broken you will soon see it.

Check your engine and transmission mounts .

Check the motor mounts. They might be worn or loose which can cause vibration felt when the engine is reved up or running at higher rpms than at idle.

Try checking the engine/transmission mounts, one of them may not have been reinstalled properly, or worn out, causing a vibration. If the car is able to move with the new clutch, and it seems to work, I wouldn't say the clutch was put in wrong. Also check the wires around the engine/transmission, you may have knocked something loose as well.
Hope this helps

Could be several things, check the following: engine mounts, transmission mounts, transmission universal joints. If its not these then you may have a bad misfire?

are the leads fitted correctly