engine stall

[coralrf]

My daughters '05 g35 coupe 6 sp stalls coming off the exit ramp-24K miles. She mentioned that lately watching it-she is coasting off the exit-sometimes in Neutral but not always and the engine rpm just drops off to 0.She then has no control. It always starts back up-so would think gas is not the issue. The previous owner changed the exhaust system but I am not sure that he did the check of the ECU reset. Any ideas?My '03 g35 coupe /auto-has started to turn off upon starting-the rpm also just goes to 0 unless I catch it and add gas via the pedal. At times it will also just die!We have taken both to the dealer with no luck.