Hi guys
impreza wrx 1993 v1 jdm

today when I was driving I stopped at traffic lights and noticed the car was idling at 1500rpm instead of my normal 900rpm. When i give it a little gas it drops back down to 900 but soon as I stop again it's back at 1500, very annoying! Also seems a little jumpy lately at low revs, what I did find last week though is that I have a big split in my turbo intake pipe/elbow. (New one on it's way in the post) I've covered the hole with the old duck tape and had no problems until now
could this be the reason for the high idle and being a little jumpie?
Thanks for any help or advice