Since using the iphone app when the car left alone for a few hours, the app can not connect to the car. The iphone app say may take a few minutes but nothing will happen.
I think there might be a connectivity issue when the car goes to sleep mode. It say " A connection to the vehicle could not be made"
I am using version 4.1 I did not upgrade to version 4.2 as I was afraid may introduce new bugs to my working car right now.
I'd update to 4.2. It seems to have fixed a lot of bugs. The problem is the car going to sleep as you said. If you don't want to update you can turn the sleep feature off and it will work more quickly.