I have a 2003 4.7L durango that won't start below freezing, if it is plugged in I can get it down to about -5 C and it will start any colder though and it just cranks. If it has been running and is still warm it has no issue. It cranks hard and I am getting a spark. I had a problem with the ground for the fuel pump relay, apparently it was getting too much current. Replaced the fuel pump and that seems to have changed the ground issue but it still won't start. When I turn turn the key on, I can only hear the pump every 10 turns or so. I have also replaced the coolant temp sensor recently.

I am thinking it may still be not grounding the pump well enough, maybe corrosion of the wire somewhere through the car, or where it hits the frame.

Any other thoughts?