Thanks for this. Have read previous threads. Any idea what amp/volt wire I should use when connecting starter solenoid to the relay?

Hi. I'm new to Landy's. Got a Discovery 1 300tdi. The problem began with the engine bringing down the revs by itself whilst driving along. As I continued to accelerate the check engine light would come on, however when I took my foot off the accelerator the problem would stop for a brief...