I have a 2yr. Old boy whom me and my husband have obtained guardianship of. The last 2 months he has started to hold the food in his mouth. If it is something he doesn't like he will start gag so I know he is not holding the because he doesn't like it. It can be his 1st, 2nd or 3rd bite, it can be foods he likes. You can tell him to eat and he will continue to shove food in his mouth until he gags because he won't swallow. You can even give him a drink and he will swallow the liquid but not the food. You make him spit it out and he cries for food give him the food and he does the same thing all over again. Feed him the same thing next week and he will eat with no problems. Why and how do I stop this?

If you feed him the same thing the next week and he eats, and he is gaining weight, and healthy, according to his doctor, then I wouldn't worry about it.
He is still very young and can't possibly learn manners too much. My little one still throws the spoon and bowl when done eating, as much as I try to teach manners. Children do funny things with food when they are young toddlers. At least he doesn't spread the food around his hair. That should disappear in a matter of time and then his food habits will probably change into a different pattern, with other things that he will prefer. Toddlers are always changing.

Since you just obtained guardianship of this child have you inquired as to his recent past and how he was treated? He may have been denied food or given too much. Once he learns that food will not be withheld or he is forced to eat too much he will come to trust you and your husband when feeding him. Give him some reassurances when feeding time comes around. And let him try feeding himself and see if that solves the problem.