Correct

扑哧

/ pū chī / 
Strokes

Example

As an Onomatope

titter; snigger; fizz [sound of tittering or sniggering; sound of snorting or fizzing]

1
Fādòngjī
发动机
pūchī
扑哧
pūchī
扑哧
xiǎng
响
le
了
qǐlai
起来
  
。

The engine began coughing and popping.

2
Pūchī
扑哧
yī
一
shēng
声
  
,
píqiú
皮球
xiè
泄
le
了
qì
气
  
。

The ball got flat with a fizz.

3
Pūchī
扑哧
yī
一
xiào
笑

chuckle; snort with laughter; titter