Hi, my engine light on my ssangyong kyron 2006, comes on and when it does, when i accelarate it goes slower, please help

If the light you are referring to is the check engine light! This generates a code when on, if the light was on then it will hold the code in the memory, if you have had the codes read then they would have been able to access the code.....what is the code? From your description it sounds like your vehicle is going into limp home mode to stop further damage, retrieve the active or saved code and this will tell you where the problem area is!