ok my car runs great, doesent overheat, nothing. ok sometimes when i start it, the car makes a rumbling noise in the front and the car and it shakes , but after a few minutes it goes away, it sometimes happens if im at a stop for a long time, the muffler also rumbles sometimes, to me it sounds like it sometimes doesent get power if i dont turn the key properly, can it be my spark plugs? what can it be
