Can anyone advise on an issue with our Fiesta 1.4tdci (2010 – 85k)?

Recently I was driving and the car entered limp mode with ‘Engine malfunction – service now’ appearing on the centre console. A service ‘cog’ warning light also appeared near the speedometer.

When the recovery company arrived the car started and ran well – a subsequent fault scan they ran indicated no faults. The car ran that evening so we decided to leave it continue driving as normal.

The next day, 100 miles from home, and the same thing happens. Recovery company took the car to a garage before towing us home. They suggested an injector issue.

Local independent has looked at the car - still in limp mode and showing the dash errors above - and the fault code suggested injector number one needs an inspection / likely replacement – quoted approx. £450 if it needs replacing (along with gaskets, seals etc).

They left the car overnight with a view to re-checking and inspecting the relevant wiring the next day (all seems fine with wiring). The next morning and the car is incredibly running well with no dash errors (!) - so it appears that the fault is intermittent / in its infancy.

Understandably the garage have suggested we have all four injectors inspected @ £25 each to save potential future issues. However, in their words, they suspect all four would come back as requiring replacement due to the age / mileage of the vehicle. If this happens then the bill to replace all four would be c.£1200.

So, what would people suggest? Replace one injector or (as is likely if inspected) all four? Will any damage come from taking them out for inspection regardless as to whether they need replacement? Apparently this is quite common with modern diesels

The car has a trade in value of c.£2k – providing it’s not showing the fault upon any inspection. Would I be best tossing it to trade and getting a new car or replacing it? We only use the car 6k p/a so perhaps a petrol would be more suited?

The car has had it’s EGR and MAF (including thermostat) replaced in the last two years so can likely be ruled out.