Vh41de 300zx - cuts out mid cruise! HELP!!

[onevia1]

Hey guys, I have a vh41de 300zx now, which is on a basemap tune on an aftermarket ecu, running Ford xr8 wasted spark system and wideband o2. it will randomly cut out, i was driving yesterday on the high way and she just randomly cuts out (crash starting doesnt work) so i have to slowly pull over to the side of the road (as my brakes go hard) then once pulled over, i take my key out instantly use the immobilizer and put key back in and she starts straight away.. but will happen ten min later again?

Any help would be appreciated thanks!

[onevia1]

I was thinking, ignition, coolant temp sensor or what else? I can hear the fuel pump still going once ive pulled over so im not too sure what could cause this?