Okay, so I bought this used rx300 90 days ago, loved the car for two weeks, then slight clicking noise coming from what sounds like right front engine compartment. Within a couple of days turned to a knocking sound. Had several mech. tell me engine mounts. Have now replaced them, twice. Still hard knocking sound and vibration when car is shifted in reverse or drive. Car now seems to be running worse, like bad gas. Mech. now says could be rear mount again. He's checked vacuum lines to front mount, says plenty of vacuum. All this to be said how can a car go from no sounds to sounding like crap in two days. makes all sorts of bumping thumping noises when accelerating. Everyone tells me the engine just moves to much. The worst thing is all of this noise cannot be heard inside the engine compartment or under the car when shifting gears, only in the interior. Makes me want to just drive the crap out of it until whatever is making the sound explodes. At least then I will know what the problem is. There are no issues once you get to 20 mph. Please help before I set this car on fire.