driving home from work 3am this mornin pouring down with rain , dual carriageway saturated, went through quite a bit of water at speed on one part of road were it had built up, and all of a sudden experienced massive vibration while in gear, put foot down and car banged like mis fire, then every time i accelerated there was hardly any power very low response, got on to my estate car back fired again then one minute there was power under pedal then none felt like someone pushing car back, drove it round then it all cleared up , car responsive again and all power back, question is what happened