shaking

[jondee86]

If it doesn't shake when the box is in neutral or with the clutch depressed,
it is pretty safe to say that it is not due to any out of balance in the clutch.

And since you describe it as "shaking" and not "vibrating", I would assume
this is a low frequency thing. Perhaps you have one weak cylinder ? If you
have a cylinder that is down on compression, it does not generate the
same amount of torque as the other three, and is felt as a cyclic pulse at
low engine speeds. At higher speeds the performance of the weak
cylinder improves, as there is not so much time for compression to leak
away.

Homegrown theory Might be worth doing a compression test tho

Cheers... jondee86