Could be a bad injector or sensor that sets the the richness of the each squirt from the
injectors. The pressures in a diesel injector system are off the charts compared to
petrol engines. So if something is out of whack in the fuel delivery system it can kill
the mileage.
Other things that kill them is a turbo issue or thermostat, but the thermostat should be
very obvious if it is not closing and keeping the engine hot enough to run at its best
efficiency.
injectors. The pressures in a diesel injector system are off the charts compared to
petrol engines. So if something is out of whack in the fuel delivery system it can kill
the mileage.
Other things that kill them is a turbo issue or thermostat, but the thermostat should be
very obvious if it is not closing and keeping the engine hot enough to run at its best
efficiency.
