2000 Other Mitsubishi Models Serivce Engine soon light.

I just bought this car from a personal owner about 2 months ago. I noticed about 3 weeks ago that it was switching gears kind of rough but didn't think anything of it really. Today the roads were reallysnow covered and it felt like the road was icy, it was kind of shaking a little. Then I stopped at a stop sign and when I took off it shook a little then the service engine light came on. I went a few hundred feet up the road and had to pull over because it had NO power. I restarted the car and the shaking wasn't there anymore but the light is still on.
What should I look for first?