2001 Dodge Neon

I have a 2001 Dodge Neon with about 132,000 miles on it. It's had a few minor problems in the past couple years but nothing major. A few weeks ago I noticed that when I'm stopped at a light the car stuttered and the lights dimmed a little. Then a couple days ago it started getting worse. Now whenever I accelerate (or attempt to), the engine stutters even worse and when I try to go faster the check engine light comes on. It feels like the car isn't getting enough power. Also, when I floor it, a weird clanking noise happens, but only once. The only way to get around is to drive ridiculously slow. What could be the problem???