I have a cen fun factor. When i try to accelerate as quickly as possible it just stays ther and revs up. Then when i let go of the throttle gently it starts to take off. What is wrong

hello READ THE MANUAL THAT CAME WITH THE TRUCK LUKE FEEL THE FORCE read up it has mucho info

Check the slipper clutch, or check the diff screw if it has a ball diff. I'm not real familiar with this particular rc so it might have a ball idff and might not have a ball diff. Those two (again if your truck has a ball diff) will be two things that would cause this. Check to see if the slipper is loose, or the diff screw is loose.

How old is it? I would say check the clutch shoes and like stated above the Ball Diff if thats what's in that truck. I had a similiar problem with my Evader and it was the clutch shoes were worn down.