97 Pontiac Grand Am Engine/Braking Issue

[sarcher116]

Every so often when I brake to a stop my engine continues to rev too high and the car feels like it's going to lurch forward. It's a little disturbing if you're behind someone. It eventually falls into normal rpm but it makes me a bit uneasy. Sometimes it feels like it is going to die but it hasn't yet. Anybody got an idea what that might be? It doesn't happen every time I stop though. It's random. Please help!! Thank you!