This TSB shows that an engine mount may be the cause of a knocking sound coming from the front of the car, near the transaxle. The noise would happen when you go over a bump in the road. I have been noticing this sound from my 2004 for a while, when driving up or down on my driveway from the adjacent road. I replaced the front struts (which were quite worn, anyway) and the noise continued. The rubber bushings on the front sway bar look OK, so I might order the new engine mount and see if that helps. It is necessary to remove the inverter first, to gain access to this mount.