@chargedewd You can press the TAB button when you are in multiplayer. And then you can go to settings and turn it off.
But you have to know that there is a speed limiter on external contracts. So that might be the reason as well.
If you want to be able to go fast you have to turn off the speel limiter in the official setting of the game and the one I just told you when you press TAB. And then you have to do a normal job. Not an external one.
Hope this fixes your issue.