Opel Astra, will be O2 sensor

Hello.
It is an Opel Astra Motor C14NZ Monopunto. To turn on, the accelerator must be tread, at Vces it is accelerated alone or decelerates and turns off. Also when accelerating the rpm first and then responds well, all normal. Review the SGTE: TPS, IAC, MAP, injector, Octane selector, coil, ignition amplifier, both the sensors and feeding voltage OK. Probe Disconnect the O2 sensor and turn on without stepping on the accelerator and regulates well, but when connecting it again, pull black smoke, and the engine after a while is covered, disconnected and works well, but it remains that when accelerating the rpm is lowered and then responds well. Will it be the O2 sensor? The car is with spark plugs, cables, filters and oil.