I have a manual transmission and can usually go up a steep hill by my house in 3rd gear. But on this occasion in 2nd gear I was unable to maintain speed even with the gas pedal all the way to the floor. It was also having trouble maintaining speed on less steep highway hills. The dealer replaced the alternator which helped, but I feel this puts my safety and others at risk because I was going much slower than expected and felt that I might not even be able to get up the hill. After the alternator was replaced, it has not happened again. There were no warnings then or after, but the dealer said there a code for fuel sensor that they could detect with their computer.