So my cars been doing this for about a few weeks now. When i go to start the car when its cold the car starts right up no problem. But saying im going from one place to another and i shut off my car and come back to start it the car cranks but doesnt turn over sometimes and then when you pump the accelerator the car gradually turns over. And also when the car i cold and you start driving the car hesitates kind of like it pulles back and then goes but when it warms up its get a little better. Could this be the spark plugs or maybe the fuel pump or injector?