Sorry only coming back now, This is an old Galloper (1991) So there are no malfunction codes. it just has a check engine light on the dashboard.
The engine is a v6 fuel injected petrol engine.
I have taken it to some local people, all reckon it might have to do with fuel injectors. just dont understand why it only starts doing it when the fuel tank gets half?
Thanks Greg, will try and get the car to a service station. But at least now I can give them an idea of where to look.