RB20DET Misfire? Stalls when idle

[regitel]

Hey guys, I own a 1989 R32 with an rb20det and i'm having issues with it.
- when cruising or under boost the car will lose power for a second and not rev when i put my foot down and then drive normally (feels like sudden braking) Only ever happens when engine is warm
- when i idle for too long the car will just shut down
- whilst idling car shutters a bit every few seconds and can notice a slight drop in rpm about a 50rpm drop then goes back up
- on cold starts the car struggles to start, it'll crank and fire normally but then revs up and dies so i have to give it a bit of a rev to keep it alive
- sits at 500rpm when cold and when warm at around 900rpm to 1.1k

mods are as follows:
Plazmaman front facing plenum
Stock turbo
boost tee
front mount intercooler
bigger alloy radiator
stock ecu
rb26 coilpacks

I've replaced my injectors and spark plugs and is still misfiring

any help would be really appreciated as ive been on this for weeks and cant figure it out
thanks

[xracerx972]

Coolant temp sensor could be bad, base timing could be off, may be fuel supply issues(dying pump or bad electrical connection), there could be vacuum leaks, dirty IACV, maybe a bad MAF. Those are the things I would be checking.. Thats assuming all electrical connectors are good as well as grounds and nothing is chafed or shorting.

*oh and o2 sensor(s) If theres a way for the ecu to spit out any trouble codes, I would see what the ecu is trying to tell you.

[regitel]

Thanks for the info
I'll give it a go and test those and let you know what happens
*cylinder 5 isnt firing (coilpack test) so could be a bad coilpack or ignition harness?