ok where ive circled in yellow, that hose, mine kept poppin off (god knows why) and when it did it would cause the exact huntin yours is doing, so i ended up cable tying it on and then it turned out it had a MINUTE hole in it which was causing rough runnin so my mate (vx mechanic) said cut it where the hole is and cable tie it bk on as i had and it ran sweet ever since, when it popped off it would hunt its head off UNTILL u plugged the hose with your finger and then it would suck air against your finger seal and run fine...now this is my first experience with F.B.W this car so sorry if im wrong but i assume its a vaccum hose where it goes i dont know tom sorry but thats your problem, if i sealed it with anything...the problem went away if i took my finger off it it would start suckin air through the hose again and huntin like hell again...chris or lee or someone will tell u what hose it is...hope this helps buddy
i'd say and again only my opinion that your gettin the problem when the engines cold as i was and when it heated up the hose expanded through engine heat and sealed the tiny hole up, thats what mine was doing.