RE: best way to tune a monster truck?..
Well, if you were running on the street, you are probably just fine. If you were running in the dirt, your motor may have ingested dirt & dust, which will effect the bearings, and potentially scratch the piston/sleeve causing loss of compression.
Do you have a local hobby shop around? No offense, but it looks like you will need some help to really get you to understand the truck and how to run it before you cause any damage to the truck.
When I talk about throttle, I mean the throttle control on the Hitec Radio.