Do you get the peach fuzzy really, really hot? Like as hot as your tap water will go? Do you put your snake in a very small separate feeding container, so he can't just go off and forget about the food?
Another suggestion, have you checked the temperatures on both sides of the vivarium?
Yes. What does this have to do with eating? But he usually is on the warm side, like 95% of the time.
Well, he may be going into the blue state and you can't tell yet. I have plenty of snakes that won't eat before they shed, and I don't figure out they were blue for at least a week, or maybe not until they shed. Is he as active as ever, or is he hiding?
You could try smaller pinks- maybe he isn't ready to make the step up. And you could try slitting the backs of the pinks in about four places, even the back of the skull.