Johnboypollockwrxra

Hi hope some body can help I'm new to this forum and new to Subaru !!! But I've got my self a 1992 wrx ra that I'm intending to use for the track but the car does have some probs that I'm trying to work out ! But one thing that I noticed it was doing that I found strange was that when I pull the handbrake the engine speed increases from about 800 rpm to over 1000 rpm when you take the handbrake off again the revs dip right down to as low as about 700 rpm before settling down again !!!! Handbrake light works just as it should and dash has no warning lights any help much appreciated