My Proto 2000 0-6-0 was the best running out-of-the-box loco I have bought to date. It is still one of the best on my layout.
You could try resetting it to factory default just to see if it clears, but I agree that it is probably best to send it back.
I just bought a new Heritage Proto 2000 0-6-0 steam locomotive (DCC & sound). In the forward direction it lunges intermittently instead of moving smooth. Also in the forward direction, I'll blow the whistle and get an eardrum breaking static sound.
In the reverse direction movement is smooth and the whistle sound is fine.
Please advise. Thanks much.