Fiesta 1998 - Faulty ECU / Imoliliser

[WOTNOTAGAIN]

I think the imobliisor on my 1998 Ford Fiesta Finesse (1.3 Endura engine)is playing up as sometimes the car will not start, even when there is sparks at the plugs and petrol seems to be getting up to the fuel injection module. When the car starts - which is 90% of the time AOK, fine, super, etc, it runs like a dream... But there are times when it just won't start, and there is no smell of fuel after trying to start it a few times, so I think it must be the imobilisor unit, as I have replaced the crankshaft motion sensor and it makes no difference.

Can the imobilisor be bypassed? easily. Security is not the problem with a car of this age, but starting is.

Or, How / Where can I get a cheap imobilisor unit