FENZ

hey all been reading up flat out but nothing really sounds like the problem i have my R33 runs like a bag of crap when its cold the problem started about three days ago when i drove home from work it cuts in and out i will be driving along and all of a sudden it starts coughing and spluttering then running normal and so on when the engine gets to normal running temp it stops and runs like a dream again so ANY IDEAS ???? i have had the car about a mounth i have rescently put new aluminium radiator and vacume lines if that might have disrupted something

Hello guys hoping u can help me out ! bought a R33 gtst about a mounth ago i love it good upgrade from my s13 i drove to work this morning car ran like normal went to work but weather was no good so didnt have to as i am a fisherman car sat for a hour 1/2 turned it on and ran like a bag of shit missing real badlly anyway had to get home about half way home she ran like gold again i noticed as soon as engine got to normal temp it ran ok again got home went back to sleep went to go for drive and same thing again ran no good until engine warmed up so buggered if i know i recentlly put new vacume lines and aliminium radiator on maybe i have disturbed something but i doubt it ????? anyone have any ideas