discovery 2 air susspension drops sudenly

Hi,
after having 3 Defender 110 countys over the past 15 years, I decided to get a disco 2, it is a 1999 TD5, but when I go over speed bumps, the first one is ok but the next one hits like a train crash, I pull over, and after a few mins, its all ok again, sometimes when I am driving down the road, the susspension at the back just dissapears for no reason, but when the motor is parked up, even for a few days, the susspension stays up, the guy I bought it of had only just had the pump replaced, and second hand bags installed (why would someone do this?) when it goes its like a sledge hammer hitting the chasis (after inspection the chasis has no rubber stops), what can it be? distance between speedbumps is about 30 yards

also, when I can afford to fit coils, does the ecu need remapping??
please help

wow

what a great responses LOL

after 2 days the suspenssion is still up????

I had a similar experience

turned out the plastic at the top of the air bag where the pipe connects to had a hairline crack in it - this resulted in the car going down randomly also was a bugger to find - would not show up on any of the normal tests was eventually found by taking the airbag off and connecting it to a airline and then submerging in water whilst moving around vigorusly

looks like I found the problem, when the rear door is opened the suspension drops, this landy is 10 years old and the rear door hinge has worn, so its a bit of a shove to close the back door, as the door has technicaly dropped and the electronics in the door are inside the lock, when I go over a speed bump the door lifts up and down with the weight of the wheel attached and triggers the suspension into thinking the back door is open !! messed about with the hinge for a while, and managed to get the door closing almost perfectley, then took it for a test run over a total of 19 speedbumps and the suspension was fine,,,, !!!!