Season the pork with salt, to taste, and lightly the dust the cubes with flour.
Heat the oil in a Dutch oven or a medium-size heavy pot over high heat. Add the pork and potatoes to the hot oil and saute until golden brown, about 4 minutes. Add the onion, poblano chiles, and bell pepper. Continue cooking until the onion is translucent, 3 to 5 minutes. Add the orange juice and cola. Reduce the heat to a simmer and cook until the liquid has reduced to sauce consistency, 40 to 50 minutes. (If the sauce has not reduced in this time, strain and reduce the liquid separately over high heat until thickened.)
Before serving, reseason with salt, if necessary. Accompany the stew with yellow rice and wilted fresh spinach leaves.