The bad thing about trying to get your car to do something by just pushing on it, is that you can't give it the sudden high impact jarring that it gets when you are driving. If you have parts rubbing against each other, you might get it to do something. That knocking is a pain. My wife's 92 Grand Am has been doing it forever. She took it down and had the struts and top bushings replaced, which stopped it for a bit, then it came back pretty quick. It shows most when you are hitting sharp bumps in the road. I keep thinking it's the two bushings in the swing arm that are worn. Perhaps when the car is raised up, they rotate a bit and the noise goes away until they turn back again after some driving. might sound stupid, but I can't find anything else and I'm tired of paying people to replace everything else.