Good morning, I have a Sentra 2001 1.8 engine and it happened to me that, when driving on the street, it speeded up only to 40-50 mph. I tried accelerating it harder, it revolutionized but wouldn't speed up. It consumes way too much fuel and also the oil light has turned. I checked the oil, which I thought might have burnt, but it was at its right level. I kept driving and the light turned on once more. It has also occurred to me that, once revolutions went down and I accelerated, the car stalled. The engine started again but it made a terrible sound, as if the rods were about to break. I then stopped at a mall, bought some oil and added it to the car but I could not solve the problem.