My 07 Expy has been blowing blue smoke on start up after it has sat for some time IE overnight or a few days, I know enough about engines to know what that means and whats causing it, has anyone else heard of or had this problem with their Expy? Mine has just under 30K and I have change the oil by Ford per their recommendation.
Late to the party but yes, blue smoke on start-up is an oil condition typically caused by leaky valve guides and/or valve seals.
What oil have you been using during the oil changes? Have you or your shop changed form conventional to synthetic or vice versa? I only mention it because swapping between the two can cause premature wear on seals. The different types of oil cause the seals to swell differently and going from one to another can cause them to fail under certain situations.
I don't want to scare you but that happened to my 03 5.4. I changed the oil religiously at 3k and used castrol syntec blend. At about 35k, the smoking started just as you described. I went to Ford and they said it was "normal". At 54,000, the motor developed a severe knock while rolling down the interstate at 70mph. It happened at the exit where the dealership was that I purchased from. I limped it in and had them look at it......I needed a new motor.