Ford Repair: mini van keeps deing?????, mini van, idle control valve

Question
I have a 98 Windstar with about 207,000 miles on it.  During the hot summer months my mini van wants to die when you first start it up.  Once it is started you have to let it "warm up" before putting it into gear other wise it will die.  ANy ideas what is causeing this.  It only happens when it is hot outside.

Answer
well there is a very common problem on those , with the idle control valve, sticking closed i would check that take it off and see if it is almost stuck closed,it is mounted on the throttle body or upper intake its bolted with 2 bolts will need a 8 mm or 10 mm to take off , try when you start hold gas pedal half way and see if it stays running or try to stay if soo replace iac  ** i would check the pcv vavle hose also know problem for big vacum leak **