The Hitachi carburetor is totally rubbish. It uses a Lambda sensor system, which does what it likes when it likes.
There is a cure however!
Weber do a replacement & conversion, which removes the need for the Lambda system, making it redundant.
It is a good old Weber Twin. Solid, reliable, & only £337 fitted & tuned.
Compare this to the Nissan advised £650+ replacement carburettor, which will still use the Lambda system.
This modification does away with the ECU (Electronic Control System) fuel mixture control system, leaving this to the garage to set via a standard mixture screw. If however, the ECU is also up the spout (known for it), then replacing your carburettor with the same thing (virtually) is going to mean a new ECU, which costs lots more £££££££.
If your 100NX is running badly, get the Weber conversion people.
The handling is good, but would be improved by uprated suspension & more rubber.
The interior is lovely. On a ten year old car, there are bound to a few trim rattles, but these are easily solved.
Air recycle switch is stuck on recycle (standard fault, easy fix).
I am trying to set up a UK 100NX club, as there are none in existence at the moment. This will be for advice & information swapping, & possible meet ups.
The site for further info is groups.msn.com/uk100nxclub/
or, email firstname.lastname@example.org