Same thing happens to my Minature Poodle. Your dog is throwing up bile due to low blood sugar. As you know, when Cody throws up, there is no food in it, just fluid. This proves that his stomach is empty. With small dogs, they can become hypoglycemic very easily. I suggest giving a few treats before bed. Or, stop by your local pet store and pick up some Nutra-Cal - it is a sugar based thick syrup that also contains many nutrients. Squeeze some onto your finger (about the size of a nickel) two times and allow Cody to lick it off. If you wake up in the middle of the night and are able to, give him another "dose" to keep his blood sugar normal throughout the night.
Let me know if this helps. Good luck!
Our oldest Dobe vomits every day to every 3rd day, exactly 12 hours after his evening meal.
He's done this for over 2 years now. Has had tons of tests, and no one can find a reason for it. Pepcid and Reglan did not help.
No special diet helped either.
The thing that has helped him the most is a small snack just before bed. The other dogs get jealous, though.
You could try adding a little pepcid once a day and see if that helps, or even Pepto Bismol tablets. Speak with your vet about it and ask him about dosages. Worth a try anyway. Has your vet run any blood work to see that all the organs are working properly? If not, that would be a good next step. Even young dogs can have troubles crop up, so before resorting to medication, you want to make sure things like the liver, pancreas and kidneys are OK.