Sounds like it might be the turbo...
I don't know enough about the ones fitted to the v6...to say what to test or how to test it...
The turbo is a variable vane unit which operates very low in the rev range.
I assume the issue is - no power at all below 2000-ish RPM and then it took off like a rocket.
So, don't thrash it til your sure what the trouble is...
but get the turbo checked out...