Controlling kart and question about time trial and challenge

First time trial, if it's suppose to be about skill and if there is no powerups why are there powerdowns and nitro? Bananas and nitro kind of defeat the purpose of driving only with skill
.
I dusted off my Logitech Rumblepad 2 and tried using it with STK but sometimes, if I get a penalty for accelerating before time, instead of going forward, my kart starts going backwards even though I'm accelerating. Has this happen to anyone? It only happens with the joypad and not with the keyboard and I also think it happens if I restart a race too many times (was trying to improve a record
), I push the stick forward and the kart goes backwards
.
There is also some sensibility that I can't pinpoint the origin, it seems that if I press the acceleration stick after I finish one race in a challenge, the next race will give me a time penalty even though I don't have my hand on the joypad. I end up with many penalties that I can't relate to any key pressing.
EDIT:
Instead of creating a new topic I'll use this one. It's the second time I finish the grand prix challenge against the 3 expert AIs with 29 points, above all others and I don't win the challenge I end up being second. The first time I didn't even had a finish screen, I jumped from the track directly to the main menu.
Do I have to win every race in the challenge to be able to win it? Shouldn't the player with most points win?

I dusted off my Logitech Rumblepad 2 and tried using it with STK but sometimes, if I get a penalty for accelerating before time, instead of going forward, my kart starts going backwards even though I'm accelerating. Has this happen to anyone? It only happens with the joypad and not with the keyboard and I also think it happens if I restart a race too many times (was trying to improve a record


There is also some sensibility that I can't pinpoint the origin, it seems that if I press the acceleration stick after I finish one race in a challenge, the next race will give me a time penalty even though I don't have my hand on the joypad. I end up with many penalties that I can't relate to any key pressing.
EDIT:
Instead of creating a new topic I'll use this one. It's the second time I finish the grand prix challenge against the 3 expert AIs with 29 points, above all others and I don't win the challenge I end up being second. The first time I didn't even had a finish screen, I jumped from the track directly to the main menu.
Do I have to win every race in the challenge to be able to win it? Shouldn't the player with most points win?