Vauxhall Zafira poor starting and conking out

I had a problem with My Zafira and left it with garage. They couldn't pinpoint problem and asked an expert who said 'fuel pump'.It led to fuel tank sucking in, car conking out, trouble starting, car refusing to start on quarter tank of fuel, odd diagnostic readings. The pipe feeding the pump was damaged and badly fitted, leading to reduced fuel going through system. The pressure was sucking in the tank and messing with diagnostic readings making it appear as problem could be a sensor. When removing fuel cap there would be sucking in of air. Don't know if this your problem without more info but hope this helps. Pete