What version of Premiere Elements are you using and on what computer operating system is it running?
What are the properties of your source media and what project preset has been selected for this project based on the properties
of the source media? What is the brand/model/settings for the camera that recorded the video - including file extension for the file on the Timeline.
a. you are importing video linked to audio into a Premiere Elements project and are hearing that the video and audio are out of sync while they are
b. you are importing video file and separate audio file, have sync them together, and then you are finding that these unlinked clips go out of syn?
Let us start here and then we can decide what next.