My 04 , 4.6 has developed a miss when first starting up after sitting over night. It seems like only running on (7) cylinders...This only lasts until I back out of my driveway an go a short distance down the road, then it corrects itself. No miss any time other than sitting for a long time. My truck has 86,000 on it... Like I said even sitting over night it does not do it every time , perhaps once a week... Any thoughts on the cause???