I started my car yesterday and it has developed a rattling sound under low load (it disappears over about 3.5k rpm) and comes back in on decelleration. No idea what I could have done? I recently had the car decatted and remapped. Have heard the injectors can sometimes cause a ticking noise but not sure how to check?! Any ideas on what this could be? Cheers!

 

The boost control solinoid makes a ticking noise, also if youve just had your cat removed a heat shield on the exhaust system could of been disturbed causing a rattle.

 

How do I go about checking the boost valve? Not too sure about the heatshields, where am I looking?

 

I meant solenoid!

 

Found the problem with big thanks to Graham at Enginemapper.co.uk! Turned out to be the wastegate was loose and making a right racket! Graham wouldn't even take the money for a pint! Great bloke and great mechanic!