As driving the car, the Engine suddenly stops for a fraction of second (speedometer going down to zero and back up in speed) with the yellow Engine sign flashing (intermittently).

When was the last time you checked spark plug connections, for deteriorating wires, old plugs, , oil in risers where the plugs are...it could be that or several other issues without being there to study your cars inefficiency..see a mechanic

With the yellow light flashing intermittently an engine stopping for a split second I say you have an intermittent lose connection some where . Losing power . check all electrical connections

If the engine sign is flashing it usually means that the car needs IMMEDIATE ATTENTION. Put a code reader on the computer see what code it's calling out then go from there, it could be your TPS, IAC or your fuel pump, FP regulator or any of the associated wiring.