VT miss firing occasionally during cold start

[gaza70]

When I turn over the motor for a cold start, 1 out of 10 times, My V6 VT Series 2 Berlina sedan appears to miss fire for about 5-10 seconds - reving doesnt seem to clear the fault, just time! (As if one of the spark plug leads are disconnected).

All other times and during driving, all appears OK. Does anyone have a a similar problem and/or solution for this problem?

I garage the car overnight and I still get this effect. 145,000 kms on clock, use standard ULP. Standard 3.8 V6 no mods yet - although thinking about a cold air intake. Thanks