musso vibration and noise?

Hi I have a 2000 daewoo musso a few days ago it started to vibrate and make a noise .
both are intermitent and get less when car has warmed up. Noise is similar to a blown exhaust but is really only heasrd inside the car Vibration at its worst goes right through the car. both seem worse when applying power and decrease when coasting.
seems to be coming from engine area but cannot see anything due to plate at bottom of engine.
any ideas?