Whats causing my barina to misfire its a 1.2 litre 4 cylinder manual 5 speed

I have changed my timing belt, i set the marks 12 top 6 bottom and it has started to misfire after i thought i fixed it, so i changed the plugs,leads,coil pack,dizzy cap and rotor button and still its running like a lawn mower, the oil is not milky, the water pressure is still good, it has me stuck without a car, Please can u help!!!!!!!!!!