Hi all im really stuck here. I have a is200 99 plate it started rattling between 1000rpm and 2000rpm after that nothing it is worse cold and under load aswell. I just left it rattling untill its got quite loud now took it to a mechanic and he had some doctors stethascopes and said the noise is very loud on the 1,2,3 cylinder exhaust manifold. He then said you have a slight misfire and if i change the plugs it will stop the noise because it is the shockwave travelling down the manifold..... bull**** i changed them and no difference nobody can identify where the noise is from can you help please lol. Cheers