Deviile 2000 DTS

Hey guys I have a 2000 DTS, was running good till the other day, service check engine light came on, the next day the vehicle started to shake at the light (like a misfire) and it studders when I pull off. I was able to take it to the autozone where it was a P0202 code-fuel injector #2 open circuit, can anyone explain this to me? And second my check coolant light comes on, but the coolant doesnt appear to be low, the temp guage will move from the middile just a tad bit when driving, but it goes right back to the center? Thank you