Occasionally, my Fiat Palio does not start when parked. I've checked and the pump does not make any sound before starting the engine. What I do is to disconnect the 12v connector, check the voltage and, if there is feeding, connect it back and the vehicle works perfectly. But it sometimes happens that the failure appears after a while. I want to point out that, at idle speed, the van never stalls nor jerks. The pump is new and I've already pressed the connectors so as to discard a possible bad contact problem; but the failure persists. What might be happening?

While driving at third gear, a noise was suddenly heard in the gearbox and the vehicle remained in neutral. All the other gears are set without a problem. Is it possible that a synchronizer or a gear or even something worse broke down? If this ever happened to anyone before, please help me with the diagnosis. Thanks.