Audi A6 ENGINE VIBRATIONS

Hi, I have an Audi A6 (1998) and engine vibrates erratically whether parked with the engine running and when driving. It started few days ago after it run out completely out of petrol and have to fill by the gallon. I stiil use it for short distance hoping that the vibration would stop, sometimes when I step on the gas I feel that there is hesitation or lack of power. Im thinking clogged injectors any ideas pls help.