2008 GMC Acadia hard shaking in low speed

Hi there,
I change my spark plug recently and from that moment problem start, first I got traction stop massage and engine light come on, the second problem when I'm driving every think is normal but when I reach low speed very close to stop my car choke very hard like jumbling over ramp and this not happen all the time, I talked the car to so many garage but they could not help, can you help me?