I only drive my Boxster on the weekends -- so it sits during the week.  I've noticed the last few times I start the engine, that a small white bit of smoke appears when I start the car.  It does not continue after that.
It's a 1999 with a rebuilt factory engine with about 12,000 miles on it.  The engine oil is full (checked via dip stick and gauage on the dash).
Is there any reason to be concerned -- or is this a result of sitting idle for long periods of time? 
 
 
Thanks to all.
-gene