hello my car as a rattling when under load like a pinking but when you pick up speed it is OK. and when you rev it up when its stud when the revs come back down there is a little rattle sounds like it is coming from the exhaust flexible bit. is there something in that bit that can rattle. also when i rev it quick i get a hissing sound. sounds like its coming from near inlet manifold or injector should it make that sound when you rev it quick.

Hey It shouldnt rattle or make a hissing noise (unless you bought it from a boy racer) sounds like a burst front pipe to me, there is part that allows the front pipe to move (flex) while the engine rocks as you rev it. It's probly burst there but you will not see it because it is behind a woven wire mesh cover but When cool (as this pipe gets Seriouly hot) you would be able to move the front pipe around, it will feel loose if it has broken at the flexi part.

What Model and Year is your focus?

Hey It shouldnt rattle or make a hissing noise (unless you bought it from a boy racer) sounds like a burst front pipe to me, there is part that allows the front pipe to move (flex) while the engine rocks as you rev it. It's probly burst there but you will not see it because it is behind a woven wire mesh cover but When cool (as this pipe gets Seriouly hot) you would be able to move the front pipe around, it will feel loose if it has broken at the flexi part.

What Model and Year is your focus?

its a 16 lx 99t reg the hissing noise is coming from the front near inlet manifold and injectors but only when you rev it quick