My '86 740GLE wagon starts and idles very poorly when the engine is less than 10 or 20 degrees (F). Idle speed is perhaps 200 rpm or less and rough and stalls out if not given gas. When it gets really cold I have to hold the gas to the floor and crank the motor 10 or 20 seconds before it will begin to fire, then I can gradually take my foot off the gas untill it runs by itself. This will be my third winter with the car and would like to fix it this time. Once it's warmed up it runs like a top. Any ideas where to start?