I have just picked up a 2000 model range rover Vouge yesterday the problem I have now is when I went to it today I noticed that the car had lowered it self to it lowest height secondly when driving along after it has risen to the standard road height I can hear the air pump still going altough this is doesnt increase the height or reduce it this is promiment especially when you are the lights this evening the car will not rise at all when you drive it please help