2002 chevy astro van sometimes won't start when it's cold outside or damp outside. I have replaced the distributor cap, rotor, and ignition coil. A dealership has had the car and could not find anything wrong. They left the car outside in single digit temps overnight and sprayed the engine with water. It started everytime. The was kept inside overnight all last week and driven every day. I had to keep outside the last few days now it won't start.