Twin Spark cutting out

[Robert Michael Waterworth <r.waterworth@domain.elided>]

I am currently experiencing some problems with a twin spark from a 75. The
car will run fine for a while and then suddenly start miss firing. This
starts off minor but within a kilometer starts to get worse until the
engine eventually cuts out. Leave the car overnight, try to start it in
the morning and, after running rough for a minute or two, cleans up. The
problem will then re-occur after an undefined period of driving from 5
minutes to half an hour. I am assuming that this is a fuel related
problem as when the car is running rough at idle both ignition systems
appear to be working fine.

Anyone else had this problem. There is no inertia cut off to the fuel pump
system so this not the problem. Current thought is the possibility of
vapour lock in the return line. The fuel tank has recently been removed
and cleaned and new fuel filters fitted.

Any suggestions would be great
Thanks
Rob

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