Our disco was leaking so we took it to the dealer. Apparently it behaved while it was at the dealer and didn't deflate. They put it up on the lift, couldn't find a problem. Service guy tells us nothing is wrong. Comes back a couple of minutes later and say the situation had changed. Apparently after they back the truck out of the bay and let it sit for five minutes, the air bag relieved itself and the rover was sitting on its hind legs again. The tech went to pull the car around and found the problem....ultimately one of the air bags was leaking. Anyway, the trick with intermittent problems is to catch them in the act and show the technician. The system isn't too complicated. You have the air bags, some lines and the compressor. There are level sensors on the trailing arms. What am I missing? If the air is leaking out over a short period of time you should here it. I don't see how the bags would reinflate if the car is off. I thought the car needed to be on to run the compressor.