That wasn't a long post
Hey, welcome to the forums..
As for your problem. First, try these steps and see if this fixes your problem..
Set the idle all the way open while running, then move the idle slower until the truck stops moving, no lower. Just before the truck/car's clutch engages and causes the RC to move.
Do this with the body off. Run it through a the 1/2 tank and see if it stalls. If it does, then there most likely is another problem. Test the engine for heat, place a bit of spit on the head of the motor, if it bubbles, there's an issue with overheating, if it doesn't, then you're fine in the department. With only one adjustment screw, it's going to be hard to "set it up". Low end and high end screws work hand in hand. But I guess sometimes manufacturers find ways around things.
Now if you're not overheating, try leaning the engine out until she gets close to a perfect running temp, I myself like 200, but other people like 220-250.. or whatnot. Just see if that is your problem.
Also, make sure there is no air leaks in the fuel system. One air leak can cause many hours of irritation, trust me, I know from experience lol! Check everything you can.
Also, just incase, let's make sure. While the motor is cold, use your finger to spin the flywheel, if it's really easy to turn, you may have an engine pretty much done. If it's tight, and takes a little force to turn over, then you hear a "pop" out of the exaust, the motor isn't the fault..
After that, I'd personally adventure into a carbuerator check.
Hope this helps you.
AoD