I'm sat in the aforementioned car by the roadside between kidderminster and bromsgrove UK waiting for the AA rescue people to sort me out.
The car started juddering then engine warning light came on. Any guesses?
Keep me company while I wait!

checked the petrol gauge?

Did you put gas in the car?

It was 2 knackered sparkplugs

Did you change your oil?

What about cruise control? Did you turn it off?

I think I remember hearing cruise control is illegal or something in UK? No?

petrol and knackered are such great words

I'm moving to the UK next year
I seriously doubt cruise control is illegal there, considering basically every European car in Aus has it

It's not illegal. Just my car ain't got it

headlight fluid, no one checks that one.

Interesting for 2 plugs just to go like that, what car was it and how was the servicing?

it is strange that 2 would go at the same time

I don't find that strange at all.

I'm assuming that it wasn't the plug going bad as much as buildup on the electrode. It's rather common on averagly maintained vehicles and some models. Also, if a bad batch of gas was gotten it could of multiplied this problem greatly.

I remember when I did the headgasket on a 1998 Ford 3.8L V6, I had to replace all of the plugs because one of them had the electrodes completely clogged and 4 others had substantial buildup.

It is an exponential effect, once the plug starts to lose spark, the burn becomes less efficient, and the buildup increases.


Now I could be wrong and buildup might not have been the issue at all. But from the limited ammount of information that was given, I'm going with that.

no - cruise control is quite legal here its steering wheels that are banned, lol ;)

zygotic - the ignition coil

i would imagine two plugs were probably buggered anyway and that your engine would still run (rough as hell) for a short while - coil i'd guess

Coil pack was changed last year, I wasn't told that I should replace the plugs 2 plugs were covered on black oily stuff and the other 2 had electrode damage, they had done 50k miles. Roadside rescue bloke said i needed platinum coated plugs at £6 each

Buildup, as I suspected


VICTORY!

one plug could be misfiring and your car would still run, but with modern ODBII systems 2 plugs can't just tlstop working without a sensor throwing a code and/or stopping the spark to all plugs. Maybe 10-15 years ago, but not on newer cars. Especially not one with individual coil packs.

In addition, by default, the knock sensor would retard the timing so much upon a plug failing that the car would not run very well if at all.