Why is there a burning smell when heat is on 2001 mercury sable inside the car Why does the idle surge sometimes when the heat is on?

Why is there a burning smell when heat is on 2001 mercury sable inside the car Why does the idle surge sometimes when the heat is on?
just want you to know you are not alone. I too have a '01 sable and I'm having the exact problems. I have approx 190,000 miles on it though.