Is it the TomTom?

try driving without sat nav for a few days,dont plug it in or even have it in the car forget you own it,then if your car does it again you will know your car has an electrical fault of its own, if the car is ok, sit on your drive and start your car,dont go anywhere,rev up the car, make sure its all still good,then plug in your tom tom and programme it, keep reving your car slightly up and down,
if it cuts out, its your tom causing the problem,it must be shorting out, but then it should blow your ciggy lighter fuse, and do no damage,trust yourself, to sort this out by reason and deduction,best of luck.
Pete

cortina pete
June 2009