Misfiring GSi trouble

[brian]

Its a standard gsi 8v engine.
Loom was a bit dodgey (lots of insulating tape and joined wire etc behind the dash) so i changed the full loom. Used a 1.2 loom and wired in the GSi engine loom including fuel pump relay.
Before the loom was taken out the engine was runin bang on and since i got it going after changing the loom there is a misfire in cylinder 1.
I changed the lead and changed the plug even though its sparking for a set of new ones. still no joy.
When i was taking out the plug i discovered the prick who had it had cross treaded in the spark plug :o but the new one seems to get good tread in. as far as i can tell by counting treads the plug is going down enough but does it have to be in an exact distance? if its not going in full im only talking about one tread at most.
any other ideas people? :?

[Novas.5u.com-Chris]

I had a knackered thread on one of my plugs and had it helicoiled, didnt even have to take the head off. If the plugs going in ok and looks like its at the same angle as all the others then it shouldnt be that which is causing the problem.
Try starting it up and disconnecting an injector one at a time. If it drops down another cylinder then you know that that particular injector is working fine. If it doesnt change the way its running then it could be a problem with that injector or the wiring for it.
All I can think of so long as the dizzy caps ok etc?

[brian]

turns out it was a half fucked coil.
very strange when the symptoms seemed to be based around cylinder 1!
Changed the coil and was grand but today its back to a weak spark again. just gonna try a few things again now. very annoying.
thanks anyway.

[boronova]

I had similar problems with my 1.2 Flair. It had been misfiring for ages so I had the coil, distributor, ignition leads replaced, and the carb cleaned out. It turns out that a garage that I had taken it to for somthing else ages ago had cross-threaded two of the spark plugs so badly that I am now having to replace the whole cylinder head, which is a pain in the arse!