I run a fixed route during work days and I use Nike+ at the same time so I am pretty sure the distance tracked is reasonably accurate. As you can see below the distance is way out this morning and the time is cut short by about 4 minutes. During the last 5~7 minutes I kept on getting " ... paused" and "resumed" narration without me pressing the button. The narration was also garbled because it repeated itself before it being finished.
Nike+ 4.25k, 30:31, pace 7:10, A/MHR = 149/159