A dash cam caught a glimpse of the pair who were stood on the corner of Walton Station Lane and Greenside in the village of Walton.
As the cars wait to exit the junction onto Greenside a lit firework can be seen narrowly missing a passing car that was thrown by the pair.
The car from which the footage was taken was driven by a woman who had her five-month-old baby with her.
The yobs, who are seen in the right-hand side of the footage before the vehicle comes to a stop, shows one dressed in a dark or black jacket, wearing gloves and is stood with a bicycle. The other is wearing a red jacket.
The incident happened on October 29 at around 2pm.
Anyone with details should contact police on 101 quoting crime reference number 889 from 29/10.