cold start problem
 

My 2006 only starts with either when it's not plugged in. I replaced the grid heater and the grid relay. It has anti-gell in the fuel also has a new fuel filter. . After I drive it , it starts with no problems and runs as normal. Any ideas?

Keep it plugged in! How cold is cold? Weak injectors low cylinder compression use of either could be a lot of things tired motor???