Went to the track today and the car ran perfect. Stopped by a friends house when I got back and talked for about 30 minutes. When I left there it started missing really bad. Feels like it's only running on about 4 cylinders. At idle my vacumn gauge is jumping all over the place. I was just driving normal when it started this. Can't find a vacumn leak. What else would cause this??? Thanks, R.B.