recently the car has been havinig trouble getting into access height. It doesn't always happen but sometimes it will vibrate and struggle a little when it goes down. Is this normal?

mine does this sometimes, usually after a cold start, not had an error messages or any suspension air compressor failures as of yet, so presume its all good. Past: Bmw M3 Coupe 57, 335d Coupe 56, Audi RS4 06, RR Sport TD HSE 05,
Current: 57 Bmw 730d Sport, 56 Merc S320 CDI L, 57 Merc Viano L 2.2CDI

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Mine has not displayed this symptom but if there is no error messages then I would not worry about it.

I say to myself, that if I ask the car to raise or lower and it takes it's time, then there is a good reason for it, such as the compresssor is not charged enough, or the car is too busy doing other more important things! 
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