Unexpected hard cut limiter problem

Hi everyone, 

I’ve got an issue with my Jimny where when I’m in gear accelerating, engine is warm and nearing the end of the tachometer (6k to the limiter 7k) the car will act as if it has a spark cut limiter; Backfires and the tachometer drops out momentarily.

This seems to happen every other occasion but seems more frequent when the car is revved out through second and then again into third.

Although this may not seem like a major issue at first, after some aggressive driving I hit the limiter in second and the tachometer went completely dead. The car wouldn’t run for more than a second or two at most and again the tachometer kept cutting out, pointing me in the direction that the ecu is cutting spark or losing rpm signal.
After leaving the car overnight it runs as if nothing happened with only the initial symptoms when hot.

Has anyone dealt with a problem like this before? And if so how did you find a solution?

For reference, the car is a g16b swapped jb33 that originally came with a g13bb. I did not do this swap myself. I have swapped ignition leads to no success. 

Thanks everyone for the help and advice!

Sounds like it's loosing reference for tachograph signal which is sensor related especially if it starts doing it when warm. Can't remember if the g series has just cam, or crank or both but I'd start looking there. It's ether sensor related or wiring especially if whoever did the switch wasn't conscientious about securing plugs etc correctly.. Also they do have a limiter for a reason being to warn you that it's not happy spinning that fast.

The G series just uses a cam sensor at the back of the engine, I have an idea that the 1.6 actually has a crank sensor but it isn't used, and the sensor wheel on the back of the cam has to be swapped over with the one on the 1.3.

Anyway, as Lambert says, start by checking the cam sensor. You can try spraying something on it that will cool it down when it starts misbehaving to see if it is a heat problem.

Is the 1.6 supposed to rev that high? The ecu won't know that it isn't a 1.3, but it might not be good for the engine.

The fact that it has a swapped G16 opens a huge can of worms - which of the G16 variants was swapped in and how was the swap done.

There are just so many different ways to make it happen, including swapping the cylinder head, complete with camshaft & all the sensors.