51,000 miles, b4 me leasing my car use to be a rental. It has no problem with starting up; but just a slight delay than normal, nothing too abnormal 2 me. When I began 2 drive it only stays on 10 speedometer, when i get to driving it cranks up slowly to 15,20 not much really over 20. When I slow down then it goes back down to 10 and stays there until it cranks back up. If I press down on the gas all the way it still does not crank; but acknowledges that i'm apply pressure; but wont go no faster. There is no visual leakage on the ground. Twice in 3 days it has stopped; but had no problem starting back up. What do you think is the problem and/ or what should I do? Reverse isn't an issue. I have no problem with reversing, just speed, gears, and the car has a stank smoke smell, and the motor shakes a bit and the car has somewhat of a loud sound. PLEASE HELP!