My Range rover suspension is play up at the moment when i start the engine the suspension is taking ages to pump up the car is showing no faults, and also when i leave it over night its not going down so as soon as i get in its ar ride hight???????? i have changed the filter and exhaust filter on the comperesser but this is not making any differance, when i use the controls on the dash it flicks between hights but taks a while to do this any idea's?????????????