Newbie with a problem accelerating

[b20wht]

Hi Im new to this hobbie and just bought a cougar sv with lrp esc and motor. Finally got the radio gear and got it up and running today. Problem I have is that when I push the stick all the way forward quickly the car just kinda of stutters until you release the stick a bit and then it gos! Its fine if you push it forward slowly just not when doing it fast. Im sure its probably something I havent set up properly but can anyone give me an idea what the problem could be please?

The tansmitter is a Etronix Pulse 2.4g. Do I need to set something up on here maybe?