My 98 Aurora stalls in colder weather after I exit the highway. I travel at 55 mph for 2 miles then enter the highway where I drive at 70 mph. When I exit and stop at a light at the bottom of the exit ramp. The car stalls while stopped. It usually stalls again at the next light a few blocks away. This does not occur if I drive 55 mphH for the 2 miles, then began in town driving at speeds of 25-35 mph. It also does not occur in the summer months. We replaced the fuel filter and used a fuel additive. Both items seem to help but only for a short while.