So I was buggering about with the electrics and shorted something out.

The car ('97 XH ute 4l auto) started to misfire soon after, so I surmised I'd blown a fuse or link, but I couldn't find it.

When I had the time I pulled each of the injector connections off and tracked it down to the 3rd cylinder. The lead was sparking so I took the plug out and there was a piece of crap between the electrode and the earth post. Flicked it out and all's well again.

The cars done around 190k and the plugs are new.

So the questions are
1 what's the likely source of aforementioned piece of crap?
2 why did No.5 injector start pissing fuel when I pushed the connector back on? Bit of a twist and it stopped.
3 Why wouldn't the 100A fusable link come out? I couldn't even lever it off.
4 When will I learn to disconnect the battery when doing electrics?

Comments, insights and flaming gratefully received.

#1 was it black? could have been carbon build up from top of piston
#2 might have moved and unseated the o ring when pushing it back on
#3 dunno
#4 never

3 IIRC, it's bolted/screwed in from underneath.

Someone confirm ??

Thanks Ranga and Snap.

1 it was black, so I reckon it was some carbon that broke loose, time for a decoke perhaps.
2 It seems to be sealing ok now, but I'll keep an eye on it
3 I was talking to a bloke at the weekend and can now confirm that it is bolted in (thankfully I didn't use too much force trying to lever it out)
4 Until something actually catches fire I doubt I'll ever learn.