Graham,
I am looking forward to your next ACtion articles on getting to grips with the Ford EEC IV EFI: When it's working as intended it exposes the inadequacy of any carburetted V8 - however some Mk. IVs are now in their fifth decade and, as Ford themselves instructed, 'sensors will deteriorate and should be replaced at intervals' not that they specified what that interval was - one presumes the replacement was 'on condition.'
In any event, as I believe you have found, many faults blamed on the EEC IV turn out to be simple old poor electrical connections as fitted to automobiles since the nineteenth century....
Thus we are long overdue a bit of a primer on the EEC IV and its associated systems. I think there must now be a significant proportion of member's cars using this fuel injection system. Two or three articles from you in ACtion would help to demystify the system and perhaps prevent members being taken advantage of by "experts."
Barrie