Celtic striker Anthony Stokes also had been targeted recently, where previously Neil Lennon was sent an explosive device earlier in the year and Niall McGinn and Paddy McCourt were sent bullets in the post.
Speaking about the sectarian attacks, McCoist said; "I think we are all sick of it (sectarian attacks). So Kyle's no different from the rest of us," he said.
"Anthony Stokes' window gets panned in, and Kyle gets his car done. It's a sad reflection on society but I still think we are getting better.
"But I don't think what has happened would stand in the way of Kyle signing a new deal. I would certainly hope not anyway."
"I'm doing okay, but I'm sick of all this nonsense - there's no need for it," he said.
"All I want to do is concentrate on my football with Rangers and my relationship with Nicola, and I can't wait for the birth of our baby in three weeks' time.
"These are exciting times for me and I don't need them ruined by incidents like this."