A little more information please.
Is it a new grill or a used grill?
What model is it?
How many burners does it have?
How hot does it get on high after about 15 minutes or so?
Can you explain what you mean by cooking the meat vs grilling the meat? It sounds like maybe the grill is not getting hot enough, but I am not sure what you mean by "cooking the meat".
Maybe post a couple pictures of the flames.
Welcome to the forum. I am sure we can get you fixed up when we get a bit more info.