I just installed an F900.With the gps antenna attached the unit starts rebooting everytime while I am driving so I cannot play neither a cd nor hearing the radio etc. but works normally when i stop.When I take off the gps antenna the unit works perfectly even while driving but without the navigation.Did someone come across this problem? I did not attach the speed wire and the reverse signal wire.Could that be the problem?

Thanks for ur help

Not having VSS or reverse connected is not the problem. I haven't experienced this, but it seems like several others have. I have seen speculation that it is a fault of the internal gyros, and I have seen some comments about corrupted files on the FLASH. You will probably have to send it for repair.