well I go start my car one day as I head home from lunch. I notice it sounds sorta wierd. I go to drive and as my rpm go up it sounds even wierder. The car seems to have a loss of power and when I acclerate hard the car like shakes and the exuasht sounds different. As I went back to school after lunch it was doing the same thing and half way on the way to school it returns to normal and my power is back and it sounds like it should. SO I figure what ever was wrong went aways. Well after school I get in my car and go on my way home its doing the exact same thing again. What could this possible be?? misfire mabye or exausht leak??? I seriously need some help this is very bad news as im trying to sell my car right now and I have no money. 