My 2001 Lexus IS300 is also giving knocking noises on moderate road imperfections, in the front RHS suspension. This follows replacement of front disc pads and shock absorbers. No problem existed in the suspension, but my mechanic detected a very slow oil weep in shock absorbers during previous service, so I decided to replace them. I have now returned car 4 times, and in an effort to find the problem The new shocks were replaced again to make sure they were not faulty! (Ultima brand) The top right suspension mounting plate was replaced in case the bushing was the cause The ball joint was replaced All bolts bushings checked/tightened, and disc pads seating checked too, but the beat goes on when the road is not smooth!.After the first visit there was a graunching noise, probably from the disturbed coils, but that did settle down after second visit. Any ideas? Help!