Ok found the problem with the engine today turns out to be the ignition amp that sits on the coil pack cover dropping a cylinder when the engine is warm, a big thanks to Andy @ ACspeedtech who has been coming out to the car to sort it out he has been running and mapping Skyline for years so knows the engines backwards.
So will have to find a second hand working unit as Mr Nissan does not sell them any more.
Available from rhdjapan for £450! but at least its new as most secondhand skyline bits are old tat
Nissan OEM Ignitor
I would lend you my spare but I'm leaving for Germany tomorrow at 5am.
Thanks for the offer Darren have found a brand new unit for a lot less picking it up tomorrow at Oulton Park.
Dave been burnt buying skyline stuff before myself hence why unless desperate I always buy from outside UK or new. If you need my ignitor as a loan the offer still stands I will be back in the UK on Friday night so could post Saturday (hoping I can find it in the pigsty of a garage!)
P.S I think the Z32 ignitor may be easier to come by and can be fitted to an RB. I think you just have to repin the plug as its wired differently so this could be an option.