99 Accent need buying help
 

I need to make up my mind about this car tonight so any help is appreciated im ususally a Dodge guy these asian cars are greek to me http://www.hyundai-forums.com/style_...ault/smile.gif
So im looking at a 99 accent not too bad of shape but there is an odd problem the engine light is on but my code scanner just a cheapie Innova 3030 says there are no codes and shows a green checkmark indicating that all is well.
Now when it is cold it has a bad miss spitting and sputtering and the engine light will occasionally flash i know that aint good also when it starts cold it will run rough for a few seconds then even out while driving under load uphill for example it will sputter then stall. As it warms up it gets better and better just with a small sputter at take off and when kicked down . Once fully warmed up it works great smooth no sputtering and starts perectly once hot.
So ? plugs wires ? Bad cat ? Any ideas ? Anything i can check quickly tomorrow when i go back to look at it again ? Any other way to get the codes from the computer maybe some sort of key dance ? I have a lot of leeway of things to check and do before i buy it but dont want to spend any $$ on it unless i do buy it .