1991 Chevy Lumina Vacum Leak?

1991 Chevy Lumina 6 cyl

My 1991 Chevy Lumina excels by itself after barely pressing the gas pedal. Then when you stop at a stop sign or red light it acts like it wants to die. I am not sure what the problem is but I have been told it might be a vacum leak. It will gradually excel on it's own. Any help you might be able to provide to me as to what this problem is would be greatly appreciated.

Thank You,
Melissa