gas smell when I crank up the truck/runs hot when ac is on

If you have a fuel smell then PLEASE get this resolved ASAP, before you have a fire!!. If the A/C over heats the truck then the engine cooling system is not working properly, so that needs to be inspected. Does the electric cooling fan come on when you turn on the A/C, because it should?

I had the same thing. Mine was also making clatter noises. I changed the fuel filter and fixed all.

possible leaking fuel rail/injectors when first pressurized leaks until pressure comes up then leak goes away, check all fuel lines and injectors when cold for signs of leakage when key turned on several times to pressurize system. cooling system overheating with ac system on and idle is due to a poor performing cooling system, improper coolant mixture, possible plugged radiator cores, faulty cooling fan, belt slipping, water pump bad, contamination between condenser and radiator and or bug screen installed in front of condenser/radiator, also you must consider ac condenser requires airflow to cool it, shroud must be in place to help pull air through radiator at an idle, clutch fan must operate correctly when hot and cause more airflow through radiator, if faulty will just free wheel and not produce desired airflow, also consider outside temperature, with the temps today 90+ systems will overheat without airflow, squeling noise from heater fan indicates worn bushings in the fan itself and the fan needs replaced.