well no, i wouldn't recommend that

unless you've been factory trained and know what to look for and change you could wind up doing more damage than the other guy did which would cost you more $$$ in the long run compared to if you just call the service tech out.

one thing you can try though is to change the performance mode, if you press the #4 key after the truck is turned on and fully initialized it should change the truck to mode 4 which is the fastest mode available. When you are driving the truck the display should show you what mode you are in. If it is 1 , 2 , or 3 this might be what is wrong. The lower numbers are slower variations in speeds as mode 4. Your operator manual should show you how to do this also.