Vibrating, shaking when accelerating and at idle

Started car one day, and it began vibrating/shaking while idling and did so when accelerating. Left it be and tolerated it for several weeks, began to notice that the gas mileage was bad as well. Two weeks ago I noticed that when I press the gas it makes a loud race car growling sound and vibrates harder. Last week I was driving and the lights flickered and then it sounded like the car was suffocating itself every time I pressed the pedal, and the car would barely accelerate until finally it just cut off. It will now start but will only run a quarter of a mile before cutting off. It smells of gas, barely accelerates, and is loud as heck whilst doing so. Car is the LS model.