i had the same engine malfunction light come on. spoke to a mate with the same model (2007 crd 3.0) and he had the exact same thing happen. went to nissan to go on diagnostics. crank shaft sensor....quoted $180 for sensor.. i just told them to reset the warning light, as i have not noticed anything unusual as far as performance or fuel economy. so far so good!! my mate has done the exact same thing.... i can see a pattern here!
hope this helps