engine light on and car shutting off

What is your question?

I purchased my Kia Spectra brand new in 2007 so i've had it approximately two years ago. The other day On my way to the movies my car just shut off while sitting at a red light, it started up immediately but, on the way home it did it again, this time with a little jerking, so the next morning I went to work same thing occurred only this time the engine light came on as soon as I started up the car. So, the next day I took my car to a kia shop, they looked at it, they put in new plugs and wires. I take the car home drives better for a while but, before I get home it stalls and shuts off at the light again and again the car starts right back up, so now the car is in the shop again. Can you tell me what type of problem this could be.