After about 20 minutes of driving in heavy rain and spray, my 2002 Defender Td5 110 starts to misfire badly, slowing down to 50mph or less.
When I stop for five minutes it recovers for another 20 minutes. I’ve checked the ECU bay under the seat and it’s dry.
What might cause this?
Dave Riddlestone, Farnborough, Hampshire
We suspect a wiring connector is allowing water in. It’s likely to be on the engine as the heat is drying it out in the five-minute rest period. A prime suspect would be the connections in the injector wiring, given the misfire. Methodically disconnect each connector on, or near, the engine and check the seating of the rubber seals, look for corrosion and spray with WD40 then refit.