Blame success? Most success includes some failures along the way. I am looking for ways to improve on that mix. I take it as a given only that improvement can be had. I do not believe I definitely know what should be done. For all I know, I might be barking up the wrong forest.
If its just a fourth quarter lead we are looking at, then the Packers are the 5th best at winning% with a 1 point lead (or more) at the end of the 3rd Quarter.
http://pfref.com/tiny/Tcj46
If I have interpreted your claim wrong, please send the link so I can look at the numbers. One word of caution with Pro Football Reference, while their links go to the right search and data, the search form itself is missing settings. So for instance each link I posted gives data from teams with a lead (or having been behind at one point) but the search form on the page does not indicate it.