I recently bought a 306, 95 model which shakes when i'm accelerating above 45mph. This stops when i let go of the accelerator. I've had the wheels balanced and the tracking done but no change. I've also noticed that the rubber around the top of the cylinder head (gasket cover i think?) is all cracked and oil seems to be escaping. Could this be the reason for the shaking? Also there is a small orange warning light comes on each time i start the car, it looks like an engine block. Could this be the same fault? Any help would be very much appreciated.