it could be a few things but the only thing I have had happen to me like that it turned out to be a bad or dirty air temp sensor it would just sort of stop the car from bosting in gear when I would get on it. Can you step on the gas slowly without actuating the turbo open and make it to redline without it happening? It sounds like you can rev up in neutral right? give us some more details it could something really easy like that sensor.