Hi all,

Thanks for your input.
I have now the problem solved.
Here's what I did:

I replaced the gearbox with a secondhand but guaranteed good condition gearbox. The problem was exactly the same!

So, this took me to my last option: The coil pack.
I replaced the 4 coils at the back with secondhand ones. Whilst I was doing this I also replaced the spark plugs.
Took it for a road test and the car was driving perfectly! All smooth, better acceleration and most importantly, no jerking anymore.
I bought 4 secondhand coils for $150.00 all in instead of $320.00 per unit as quoted by the Honda stealer.
There was no visible damage to see on the coils. All sparkplugs looked identical, so, I still don't know which coil played up.
I am of the opinion the coils must break down internally once they are warm/and under load.

Hopefully this information will be helpful to Jazz owners.