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!