My 2001 Ford Focus starts with a noticeable vibration and noise just like capgirl49. However, after driving a long period, like well over the half hour mark, the vibration stops and the car is quiet and back to normal. Is this a timing issue and possible problem with the PCM or some other sensor(s) issue?

Thoughts:

. Stones in the engine mounts?

. Transmission shimmy, due to not changing the automatic transmission fluid (Mercon V) and filter? This should be done every 30,000 miles.

. Incorrect engine oil viscosity?