This is a 2005 RSX base model. Upon acceleration there was a slight abnormal vibrating sound during initial acceleration, and upon further investigation I noticed when the engine was under a load, it seemed to move more than it should. I verified this the old fashion way, put the car in gear, hold the brake and give it a little gas. I discovered the motor mount located on the passenger side of the vehicle looked as if it had come apart. Since the car is 16 years old, I decided to replace all 4 motor mounts. I am not a novice at automotive repairs, I used to be a mechanic. I replaced all 4 motor mounts with aftermarket "rubber" mounts. Everything was torqued. A few of the old ones showed evidence of rubber deterioration and the passenger side mount was in 2 pieces. Everything seemed to go OK, however after all the mounts were replaced, there is now a sever vibration through out the vehicle while driving and at idle. The original vibration sound is gone. I have rechecked the mounts and all the bolts seem to be tight. I am wondering if that mount on the passenger side could be defective. I should note that there wasn't any "physical" vibration prior to replacing all the mounts, the problem was more of an abnormal sound during acceleration. Any ideas? And I appreciate all the assistance.