I'm getting a rattle from the exhaust and a random misfire code. I assume the cat is dead?

Will I get any codes if I knock out the inside of the cat? Will the engine switch to open loop?

If so, how can I get around the problem?

Cat won't usually cause misfires..... shouldn't go open loop if you remove it, if it chucks up cat efficiency errors then just remove the post cat lambdas and tie them out the way but don't unplug them and it should be OK... Pete
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2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand Sold
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Sold
2002 L322 Vogue 4.4 V8 Epson Green (Fatty Offroader) Sold
-Click for Project Fatty off roader-

Thanks Pete

The BMW forums were saying that bad cats can cause a misfire, maybe it's a quirk of the m62.

It's gone from a misfire at WOT to stumbling intermittently at idle, not bogging down. Could this possibly be a dirty MAF? It has an oiled wire mesh filter and I'm waiting for a dry AEM filter to arrive in the mail.

Also had some oil on spark plugs so changing valve cover gaskets next week.

Oiled air filters are infamous for causing MAF issues if they have excess oil on them, as it coats the wire in the MAF as the air blows the excess oil off. That's it then...... 2011 Range Rover Vogue SE 4.4 TDV8

Previous cars :
2003 Range Rover Vogue TD6
1999 Discovery Td5 ES
1995 BMW M5 3.8 6 speed
1992 Range Rover 3.9 Efi Vogue
1992 BMW M5 3.8
1988 BMW 735i SE
1989 Ford Sierra XR4x4 2.9i
1981 Ford Fiesta Supersport

Last edited by mjdronfield on 11th Jun 2015 9:43pm. Edited 2 times in total

And oily plugs will cause a misfire as well.... Pete
__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand Sold
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Sold
2002 L322 Vogue 4.4 V8 Epson Green (Fatty Offroader) Sold
-Click for Project Fatty off roader-