Hi All,

I have today had a bit of lumpy running and fault codes

P0301-00 (74) Cylinder misfire detected
P0316-00 (74) Misfire detected on startup (first 1000 revolutions)

Codes were read on the GAP IID tool. I can clear these but they re-cur and put the car into a limp mode.

I gather these faults can be caused by plugs, coil pack or injectors. The plugs were all changed approx 18 months (less than 4000 miles) ago, so probably not those.

The car is a 2005 RR Sport, 4.2 supercharged with approx 125k miles.

Any ideas where to start looking?

Thanks,
Alan.

If I were you Alan, I would start by swapping components one at a time between cylinders and see where the fault moves. That way, you'll be able to identify the correct component to replace. Kev

MY2014 L405 RR Vogue SE 4.4 SDV8 in Corris Grey
MY2010 L320 RRS HSE 3.0 TDV6 in Stornoway Grey

Cheers for the reply. I've ordered a couple of coil packs as not too expensive. If it solves the problem then I'll probably change the other 6 later as they're probably all the same age. If it doesn't solve the problem then further digging needed.

Just thought I'd close this one out.

I bought a used coil pack and fitted it this morning. Job took approx 20 minutes and everything working fine again.

Not sure if I'm going to keep the car, but if I do I'll change the set for new ones as they're all the same age (ish).

For info, bought the part for £12.95 from 'Gentlemen of Salvage'. I've used these guys before for some very cheap and sometimes quite expensive used parts. Their stuff always works so I'm happy to plug them - the stuff also arrives cleaned and generally tested, and pretty quick.

Great news Alan.

I've used Gentleman of Salvage before too. They've been very helpful and always provided a good service. Another thumbs up here. Kev

MY2014 L405 RR Vogue SE 4.4 SDV8 in Corris Grey
MY2010 L320 RRS HSE 3.0 TDV6 in Stornoway Grey

Second from me, very good people and parts always top notch. Steve

2005 2.7 TDV6 HSE, ongoing project.
1998 Volvo V70 R auto FWD, mothballed future project.
1999 BMW Z3 (owned from new) garage queen.

And a third from me, pleasure to deal with every time.