A stunning car with low mileage but it has been a constant source of problems since I purchased it two years ago. Can anyone help me diagnose the latest fault. I recently had two new rear tyre fitted.. This may be a coincidence but now the rear suspension keeps dropping when it is parked and left unattended. On turning the ignition on it comes up with the message SUSPENSION FAULT. If I start the vehicle switch it off then back on again the error message goes. Just to add to the mystery some times the suspension drops within the hour but the next time it stays up overnight. I ruled out the compressor as once the engine is running the suspension rises immediately. It is an even drop across the rear so I ruled out the airbags. Please can anybody offer any suggestions. I have a reasonable knowledge of mechanics but obviously not air suspension.