After replacing and cleaning different things my dealer replaced the fuel pressure regulator yesterday and it finally fixed my rough idle and stalling problem!! My VX used to stall once in a while and after 3 trips to the dealer I thought that I will just have to live with that. But I got a call from a dealer and they said they put an order for a fuel pressure regulator (it was backordered) and will replace it - under warranty - even though my warranty expired already. The part finally arrived and they replaced it yesterday. I noticed the difference right away as soon as I picked up the car. The engine works like new. I get very smooth idle and it hasn't stalled yet I think my problem is finally fixed. If you experience rough idle or stalling, have your dealer check your fuel pressure regulator.