Can anyone help? My 2006 v6 has 55k miles and in generally great shape. Lately it has started briefly shuddering and shaking when it is in gear idling at a stand still, and the brake is depressed; and also the same position and the windows are raised, when they reach the top it shudders. All filters, plugs, wires, etc. were replaced last fall. This just started a month ago or so. I added fuel injector cleaner and it made no difference. I am guessing it is an electrical problem like a short since it happens when the windows reach the top. But otherwise I would guess it must have something to do with the brake system since it only happens in both instances when the car is at a dead stop and the brakes are being depressed. I haven't got a clue, do you?