AUIII XR6 VCT, hard starting, high idle, maybe running a little rough?

[LukeyST]

Hey everyone,

Got a few concerns with the ST, and I want to get them sorted.

a) Ever since i bought her (in January) shes tended to cough a bit when starting. Like it will crank over ok, but once it starts the revs fluctuate and it dies right down, then she will generally return to idle and be fine, but sometimes it will stall completely : Sometimes she'll start no worries at all, i can't pick any consistencies but :

b) What rpm should it be idling at? Upon starting, and returning to idle it will sit at about 900-1000rpm, but after driving for a while and returning to idle it will sit at about 850-900rpm. Maybe the VCT's just idle higher? Not sure. I thought the idle should be about 700rpm.

c) Up high in the revs under acceleration, it seems a bit course, but i think im just used to my EL, which had the cam timing and ignition timing advanced which seemed to make it a bit coarse low in the revs but smooth as silk from 4500-6000rpm. Just thought i'd ask the question, as it might be related to a) and b).

So was basically wondering if anyone knows what causes such issues, i've been thinking coil pack, injectors, crank angle sensor, oxygen sensor, idle sensor?? Dunno. I'd just like to get a more definite answer/advice before i start buying parts only to find it doesn't change anything.

The car is an AUIII XR6 VCT ST. Manual, 130,000kms. Has x-force extractors but stock cat and system. I adapted a pod filter into the box and i've got a hole cut in the front of the airbox. I recently changed plugs and leads, so confident its not that. Also, i only ever fill it with BP ultimate, not that that should effect it.

I think that 'bout covers it _2:

Cheers.