Why isn't my bp eating?

[Lord Sorril]

the temp of the warm end Is about 90 and the cool end 70 to 80.

Given that the snake is 3ft long and has a good feeding record--I would not be concerned for at least a month or two. Very possible that the snake just isn't hungry.

If you suspect there is an issue: The first thing I would do is check the exact temperatures within the enclosure. For my collection: anything below 78F is too low, and hot spot surface temp should be at 90F (or within at least a few degrees). If you have a day/night fluctuation in temperature due to the winter temps then a thermostat (or two) connected to your heat sources should solve this issue.