I started my duratec for the first time yesterday.
It started first time but its only running on 3 cylinders.
I've checked the spark and that seems ok.
I swapped the injector connectors over on that bank, but still that same cylinder does not run.
Injector resistance measures the same as the others.
So I'm guessing it could be a faulty Injector?
Any other ideas?

Squirt some fuel down the throat manually if ITB's that will tell you - also if the exhaust is stone cold then that will indicate something definitely wrong or if its actually warm but cooler than the others then that will give you something else to think about.

Pull injector and see if it's squirting into a coke bottle? Or swap with one of the other injectors to see if the fault follows it

no1! is the plug getting wet? if not give the injector a tap it may be a bit sticky.

if the plug is wet then its either a spark issue or something mechanical. have you done a compression check?

I've had a similar situation and was a sticking injector (wire up 12v and listen for it to click). Just to check are you happy with compression on that cylinder (remove all other plugs and turn over by hand).

Cheers for the pointers.
I've not had chance to look at it today as moving my son home from uni.
So its been a day of worrying about it

A mechanics stethoscope should let you hear the injectors working, if you pick one not working check it is getting a signal using a NOID light which is really just a 12v LED.
As already said a compression check is a good idea.

Well tonight I got it running on all 4

The throttle body was closed a little more than the other 3 and I had it set so rich that that cylinder was flooding.
Leaned it up a bit and all seems good. I originally set the fuel on the megasquirt to 440cc injectors and the pressure to 3 bar but that seems way to rich.

Doesn't run particularly smooth but that's for Dale at Bailey Performance to sort for me when he gets it on the rolling road.

Just a small coolant leak to sort.