Our recently bought 1996 Defender 90 300 Tdi had an intermittent, completely random, loss of power problem, so we set about trying to locate and rectify. We searched this forum for ideas and tips and then set about trying them out:
1. We changed the fuel filter and put a diesel cleaner in.
Test run - same problem :frusty:
2. We drained the tank and filtered the fuel - checking the condition of the breather hose at the same time
Test run - same problem :frusty:
3. Cleared the fuel line from the tank through to the fuel filter.
Test run - same problem :frusty:
4. Checked the fuel lift pump and supply to the injector pump.
Test run - same problem :frusty:
5. Cleaned the fuel adjustment pin
Test run - same problem :frusty:
6. Discovered that the connection to the fuel solenoid cutoff valve was woefully loose - still on the spade connector but really really loose - therefore crimped the connector so that now it sits snugly onto the spade and doesn't wobble around
Test run - WOO HOO :rofl:

We will give it a real run tomorrow and see if the celebrations were premature...