About a month ago my car died and I found out it was to to the crank shaft sensor. I had the crank shaft sensor replaced. Ever since then I have had major power loss. I have taken it into nissan three time and each time they said that all their diagnostic tests came out fine. There is nothing wrong with my car. Can someone explain to me then why my car, with only 50,000 miles on it, takes off so slow and why it is having problems climbing even the smallest hills? Has anyone else had this problem?? And Is it safe to drive it like this??