right, had a horrible intermittent misfire, in fact complete cut out thing going on, on my cav C20NE. it was flickering the ecu light as it tried to stall but it didnt register any codes, apart form the items i disconnected while it was running, to try and find the fault.
it did actually stall a few times, but it was doing it mostly at low speeds, changing down, or when idling, but it seemed to be worse when going slowly, or stopped, when there was no air flow through the front.
Anyway, after much searching of forums, and having been told the coil never fails, i tried all the usual suspects.
New fuel pump relay, no better;
ICV, got 4 now, some better than others, no better really; TPS, cleaned, tested, squirted it, same story;
Fuel tank vent valve, disconnected for a while as there was a big whoosh of vacuum when filling tank, no better,(its meant to be like that, for the vapour in the tank thing;
leads/plugs/cap etc, all new before i got car, cleaned it all again. idled better, but still cut out now and again;
Crank angle sensor, hmm, great fun swapping that on an aircon/power steering cav, no different;
Found a few slightly loose hoses, but no problem really, tightened em up;
even retorqued the nasty pattern head gasket, as it was pressurisng the coolant a bit, found the fan switch was U/S, fuse blown too, wasnt helping in traffic;
went to the scrappie, got a spare coil, put the tools and coil in the boot, thought i'd go home and change it, before i did, it didnt splutter again for two days. I think the car got frightened at the scrapyard, there was one of its 16 valve sri friends in the same colour on the pile looking at it for 15 minutes. perhaps it thought i had enough of it, and was arranging drastic crushing measures! any way, it started doing it again, so hey presto, the other coil fitted today, and it seems fine. nearly 70 in second and 100 in third. must be ok

moral of this story:-
1. dont spend any money till youve done all the cheaper options. borrow some bits off of another car,
2. nick as many fuel pump relays as you can from a scrapyard (motor factors were 27), i know, there free if the scrapyard had have been open!)
3. dont trust people who say they think they know whats wrong
4. trust your instincts and change the coil first

cheers lads.
looks like i will have to wait till it lobs a rod out before i go for an XE!