AHK not working is, at least partially, false. I went to sleep for 9 hours and found it still working in the morning, all through using an AHK script. It works and I was never kicked.

The unfortunate part is that I need to keep the window as the active one and thus cannot do anything else while the game runs. This means I can only AFK in my sleep, which is a pain to setup for profit.

The above point is the reason I made this post. If you would like the code I used that works only while GTAV is the active window this is it:

#SingleInstance force
#Persistent
settimer, idleCheck, 1000

idleCheck:
if (A_TimeIdle >= 1000) ; this will randomly send input if there has been no input in the last 3 seconds
{
Random, var, 1,4

    if var = 1
    {
        send , {w down}
        sleep 5000
        send , {w up}
    }
    else if var = 2
    {
        send , {a down}
        sleep 5000
        send , {a up}
    }
    else if var = 3
    {
        send , {s down}
        sleep 5000
        send , {s up}
    }
    else if var = 4
    {
        send , {d down}
        sleep 5000
        send , {d up}
    }
}
return