I have a strange thing happening, if the outdoor temp is around 0 deg C, the car won't start on first try, I have to keep the key on while it cranks enough cylinders to fire and start. after it has started it runs fine. At -5 or so, I have to try numerous times to get it to go. At -10, there was no signal to crank the starter. My battery is two years old and I replaced the glow plugs with no change. Any clues as to what is going on? Any help would be great, thanks.