I have a 93 Ford Crown Victoria and it is leaking oil and, it sometimes let out quite a bit of white exhaust smoke when the I hit the gas (only when the car was sitting idle for a while it lets out the smoke). It also begins to make like vibrating shudder sound while I drive if I go over 55. The sounds like it comes from underneath my car n it makes the bottom vibrate. I also took it to get read at a auto store and the scanner came up with a EGR code. What is causing all this?