Ok, update on the situation.
2 months warranty void was too much for the shop, so I decided to open it up myself. Cleaned all the pedals, tested the accel pedal and it worked!
I put the bodomplate back on, screw in some screws and turn around the set, suddenly my software says the pedal is at 70% and it stays there.
I unscrew everything again just to find out everything works like normal again, so I get the screws back in, same thing happens as before.
I unscrew again, tape the wires into place, screw everything back on, and it works! I put it in place under my desk, and suddenly software says it's at 20 procent.
Weird thing is, I'm not touching it and it's dropping, it went from 20 to 15 and now it's at 5, when I use the pedal, it always goes back to 5 procent.
Any ideas on what this is, I have no idea what's causing it.