Have you updated Premiere Elements 13 to 13.1 yet using an opened project's Help Menu/Updates. If you have, did the problem exist before the 13.1 Update?
What are the properties of the source media? And, what have you manually or the project automatically set as the project preset to match the properties of the source media?
What is the composition of the Timeline content? What is its total duration, and what is at the specific point where you get a slow or stutter? Where is that location in relation to the total duration of the Timeline? Is there an orange line over that area of the slow or stutter?
If you export the Timeline to a file saved to the computer hard drive, do you see this problem in the playback of the export in your computer player?
Please do not hesitate to ask if any questions or need clarification on any of the above.