Maybe that when the chassis shifts for the approching turn you're loosing ground. Check all of the ground wires: engine to body and chassis, engine to negative post. Not knowing what type of ignition you have, just make sure that all of the componits that need to be grounded are grounded good. If you only have a ground going from the battery to the engine then you also need one from the engine to the fire wall.
Does it do it when the engine is running and the car setting still in neutral or park?
Another thing to check is if you have power steering, you mave have a valve in the system hanging up, building to much pressure and choking the engine down. If you do have power steering you can check this by removing the belt for the power steering pump, cranking the engine and trying it in neutral or park.
I hope this helps!