First you have to determine the cause. Brakes can be dragging and getting real hot. You would feel that by standing next to one of the front wheels. Parking brake cable could be rusted in the partially-applied position. You'd feel that by one of the rear wheels. Could have an engine misfire. You'd feel the engine shaking. Could have a plugged catalytic converter. You'd hear that at the tail pipe as a weird hiss instead of the normal exhaust rumble. The common thing is someone is going to have make some observations before we can figure out the cause and remedy.