2005 Tucson stalls out when accelerating
 

We bought a used 2005 Tucson in Oct. It ran fine the first 2 months, but now has a problem. It starts fine, and seems to idle fine, but when I accelerate it starts to "buck" real badly and has a hesitation to it also. It will stall out every now and then, but starts right back up. I can eventually get the car "up to speed", then it seems to run pretty good, with only a slight miss here and there. Has anyone else had this problem? The car only has 15,000 miles on it. Any suggestions what to look for before I head to the dealer?? Any help is GREATLY appreciated. THX, Dave