ISSUES WITH MY 4.4I 04 X5. !!PLZ HELP!!

[abtin1198]

I own a 2004 4.4i X5 and it suddenly started acting up. when driving at a slow speed or when my car is in park position it just shuts down for no apparent reason and i have to start the car again. Also when driving at speed of 60 or so my car does this really crazy jump where i have to push my breaks so i dont hit the car infront of me. i took it to two different bmw specialist and they did a dygnose and nothing came up and all was good, just few codes and they cleared it but it didnt change nothing. couple times when driving all the lights on my cluster came on and i got the message saying " Transmission & Engin safe fail program" i shut down my car for 15 minutes and start it again and all goes off. I would appreciate if someone had experienced the same or if could tell me what to do??? thanx in advance guys.