As I checked my timing/idle today I suddenly had billowing white smoke from the tailpipe. No oily smell, lots of condensation. I assume that the head gasket gave up. However, as I drove it I was blowing smoke then it nearly quit. 1) Why did it nearly stop? 2) Any temporary fix - leak stopper - until 3/30 when I have a week off? 3) Will this completely f-up my emissions?