As all of you know, Melbourne had a little bit of rain over the weekend. Driving home from the city I noticed an intermittent 'banging'. It was more pronounced when I accelerated, but would also appear when driving over a pot hole. I got home and had a look, but the undertray and everything was all still intact. I left it overnight and then went for a test drive the next morning to find the problem. However, it had gone completely? Is my car allergic to water?

Any suggestions would be appreciated.