FWIW, I had pretty much the exact problem described in the original post: 2005 4.4i about 40K miles, kept in garage, and this past winter (midwest) there were a handful of occassions where immediately on start-up the SUV began to stutter and shake violently until it either died, or I put the car in reverse and started driving. On a few occasions, the Service Engine Soon light came on and I took it to the dealer ... the only error code was something about a fault due to "ambient vehicle environment." At about the same time, I also noticed that the engine was generally idling more roughly than usual and at lower RPMs. Long story short - the dealer replaced the intake manifold ($50 under certified warranty) and the problem vanished. Hope this helps someone else.