456 '95 Starting issues.

Looking for pointers on curing my '95 456's warm up issues. It starts instantly when it's cold, and being in Canada, that means quite cold. But during warm up it idles really high, cycles dramatically, is totally gutless, stalls easily and reeks of unburnt fuel. If it were carburetted (like my 308) it would be an easy fix, as the symptoms are of overfueling/choking and/or a massive controlled vacuum leak? (The people next to me at a traffic lights really think I'm a bit of a tool revving my engine.) Once thoroughly warmed up its mostly fine, but if I shut it off and then go to restart it warm, it has to crank way to long before it will catch and then again, runs very badly for another 3 to 5 minutes, and stinks of fuel. It feels like a temperature sender is not telling the fuel injection that the engine has warmed and is continuing to create a stone cold start scenario when not required. I doubt its that simple.
If anyone has any suggestions or has had this problem and cured it, tips would be appreciated. Thanks.