Seafoam. People's methods vary but here's mine:
Run the truck till the motor is fully warm.
While running, slowly pour half the can into the carb while feathering the gas so it doesn't stall.
Unhook the brake booster hose on the booster end and put the rest of the Seafoam through there.
Shut off the engine and let it sit for an hour.
Fire it up and go beat the bag out of it till it stops smoking!
Now you can just attack the outside of the carb with carb cleaner to make sure all the linkage is nice and clean.
That worked wonders for me. I've literally done it on every car and truck I've owned... even my motorcyles, garden tractor, you name it! Stuff is magical.
As for adjusting? Dunno but I'd leave it alone till you clean it well.