getting rougher on start up

[uglymug]

Until now my 350i was behaving itself well. But recently everytime I start it it gets rougher. Start routine was usualy turn it on and let it idle, then it would get slower until it was warmish.
Now its by using the throttle until its warmish, and sounding like a misfire. Quite a strong smell of over fueling maybe! It will not retian its smoothness until its warm. ( does this make sense ! ).Then it goes like a beauty! Not using the CSI. Other than that very pleased! Any ideas? Have looked thru the search, but to no avail............cheers UG

[leorest]

I'd start with checking for leaks on the induction side and run a bottle of your favorite injection cleaner through the tank.

[rev-erend]

Could also be a misfire.

Easy to check - remove each plug lead in turn
and see if the engine runs worse - all should except the culprit !

Obviously don't do this with the engine running..

[350zwelgje]

The dreadful coolant temperature sensor can cause this. Did you replace it recently?
And as Steve Heath and others reported, even if you replaced it by a new one, this could be malfunctioning as well! Oh, we love our spare part suppliers, don't we?

Rob