I've just seen another post on here about the user's XJ not starting up https://www.jaguarforums.com/m_65233/tm.htm
Well I've, in the last 2-3 weeks or so have started experiencing a similar problem. My '98 XJR has been starting fine every time, but recently, on starting the car, there would be absolutely no power at all whatsoever.
Anyway, I traced (i think)the fault to the braided ground stap that's connected from the negative terminal of the battery to the body work of the car. Every time I 'wiggle' this cable about, the car would be fine. The connectors on both ends looks and feel very solid.
So my question is, Would replacing this wire/strap resolve the problem? If so, does anyone know the officially name/part number for it?