Broken Screw

I just went through a similar situation on my Impala. I had 4 broken exhaust manifold bolts. Two came out with an extractor. Got to the 3rd one and I broke the extractor. I had to use a die grinder to remove the broken off piece of extractor. Then I welded a nut to the bolt and it backed right out. Did the same on the 4th bolt, worked like a charm.