Don't get me wrong, it's wonderful to see the IR18 in AMS2 - also lovely to see more interest in modding the game! However after a short drive, I noticed that throttle application feels a lot different to the cars already in-game, it's like the torque curve is interpolated - Niels Heusinkveld has a great video on this topic if people don't know what I'm talking about. Unfortunately because of this, the car doesn't quite feel as playful on throttle as I had imagined
If it's still not working with that in mind it could be that AMS2 has reset your controller config (has happened to me) or that you got a dodgy download and would need to download the mod package again to fix it... We've had a few reports of this being the case with weird things happening with the mod, I've had a recent download test from here give me no UI and missing drivers... So it's worth trying just in case...
Hope this helps...