well its not really cold out maybe 35-40, but cold for central texas

my 96 4L started idling around 250-300 rpm

dont know what it could be

warming itself up.
these things have a mind of there own

what kind of oil you running? 10w 30 may take a while to thin out, 5w 30 not long. just thinking outside the box.

MAT sensor may be going out. It tells the computer to change your fuel air mixture based off of temperature.

At least that is how I interpreted it out of the book.

mine dies when its really cold sometimes. all i do is drive it until it gets atleast above 100 and then it will idle fine again