Hi Guys
I have been having an issue with my 2003 318i for a year now where it makes this horrible rattling sound when cold, It sounds exhaust related but with the help of some mechanic friends we have failed to pin point it.
recently the engine light came on and the code came back as a catalytst efficiency threshold issue p0420. It occurred to me that my issue is almost certainly a busted Cat causing the noise.
I have been looking around on Google and have found that its possible to remove this entirely which as I understand wont fail a wof in NZ.
From what I can find this was straight forward on older models but is hard if not impossible to do on newer models with front and rear 02 sensors. What I am wanting to clarify is if doing this will create any ill effects including triggering error lights / codes....
Thanks