I suggest you check the wiring and connector goes to the MAF.
Here is a general video to check voltage and ohms through and across the wiring connector at the MAF. But you need to cross reference it to your Skyline voltage spec when checking voltage while idling. Probably there is a video for Skyline but I do not have it. Hope this helps!
https://m.youtube.com/watch?v=a6eaOd3ihiE