Engine cuts out around 3000 rpm with vehicle in park.

It is designed to do that above 3000 RPM's without a load on the engine. It is called a REV LIMITER. You need to take it to a parts house and ask before hand if they can code out your computer free. Make sure you get the P codes, P0000 something. Then post them here.

need to know what the DTC is, but it sounds like a torque converter problem