Jetta TDI A4 engine dies at 4600 rpm ECU bad??? help

I have an 03 Jetta and when I hit 4600 rpm the engine shuts down in motion. I pull off reset the igination and the car restarts. check engine light comes on the fault code the a speed crank senor which I have replaced 3 times so I know thats not it. Its been in a 2 different shops and now sits at a VW dealer. They are tell me they dont really know the prob. They think its a Bad ECU or bad injector pump. But they cant get an ECU with out stealing it from another car that comes in for service or make me pay for a new one even if thats not the prob. I have contacted VW of USA and they told me I"m screwed and that they are not going to help me out at all. I think this car is a piece of shit if things start to go wrong and even VW cant tell me what the problem is. I dont recommend these cars if this is how customers will get treating. But if anyone can help me out. or wants to buy my car I will sell it for cheap