S70 T5 misfire

[Doingitsideways]

So, seeing that York is next weekend, the S70 has started playing up.

I cleaned the engine bay today with my favourite pound shop cleaner of choice, followed by a quick swill with hot water, being careful around anything sensitive like MAF etc.

Left for a few hours drying out in the sun, then started, all fine.

Idled for a few minutes, then started missing, so thought I'd take if for a quick run. Something's probably got wet was my thinking.

Got progressively worse to the point of being almost undrivable, prob only firing on two cylinders, managed to nurse it home.

Started pulling things off, found the dizzy cap a little worn and dirty, same with rotor arm, so cleaned them with contact cleaner, then found three spark plug chambers full of water, so mopped them out and it started fine.

Took it for a run, seemed fine, had a go with a Merc C320 CDi, neck and neck, then started missing again, but maybe only on one now.

Later on It started and ran fine, until giving it some welly when there was a definite cough at high revs, but no misfire this time.


So, I'm going to change the cap and arm, but has anyone else got any ideas?
The coil is reasonably new.

Car's pre ME7, obviously, MTE mapped, 16T blah, blah...