As soon as your boss even intimates that a promotion is in the wind, get him talking terms. If he agrees, put it into a memo with his name on top. Argue for authority. If it's too late for a firm agreement, you may have to lean heavily on the boss to get your promotion. Argue that getting the promotion will help you do the job more effectively.
Chances are, that's true.
Without the title, the authority, and the budget, you're probably facing real constraints. The boss is more likely to listen if your focus is on productivity and profits rather than a higher salary and loftier title. Taste the baloney. If your boss continues to play this game, you're a fool to tag along. Once you recognize this flaw, you should stop taking your boss seriously, and don't bank on any of his promises.