knocking/tapping

[bros400]

watsup guys!the gf has a 01 toyota yaris 1.1 vvti i think it is!when driving mostly when cold i can feel a constant tapping which gets faster as the rpm goes up!also it sounds very rough and engine looks to be rocking/vibrating in the engine bay!i have taken each stick coil off 1 by 1 to rule out misfire which no cylinder is misfiring!all of the mounts seem pretty good too!anybody got any ideas?also when i first start it up from cold and giv a little rev i can hear a hiss as the rpm drops!almost as if its a vacuum leak but i cant for th life of me find a leak any where.

cheers in advance for any help!