Tacho freaking out then won't idle

[Yendor]

Mine is A 2005 td inter-cooled .. I have been looking for a Description of the injection system . It has one injector with A wire on it ! the Tacho is intermittent thanks to all

With your vehicle start by swapping the ECU relay. It's located above the fusebox inside the vehicle. You will need to remove the plastic trim above the pedals to see it.

The ECU relay is the top relay. Just swap it for now with the middle relay (interior fan).

Also check and clean the main ECU earths. They are connected to the engine inlet manifold about half way down the engine on the RHS.