To make a series of soft explosive sounds, like water hitting a hot pan. Also, to speak in a quick and unclear way.
Sputter can make people think of frustration, surprise, or a broken machine.
Examples:
The bacon sputtered in the pan.
The old car sputtered and stopped.
She sputtered out her words in anger.
The engine sputtered like it was talking.
The fireworks sputtered and then went out.
The water sputtered and made a funny sound.