Why doesnt the carburetor on 1992 Mazda B2200 pickup work at full throttle?

To keep things simple I would remove the air cleaner housing the entire unit.Just note the several vacumm lines you will disconnect locations.And clean the carburetor extremely well with carburetor cleaner inside the part and use some brake cleaner on the outside(Just use the brake cleaner only on the linkage).I would use some liquid wrench to lubricate the moving parts on the outside of the carburetor only.Liquid wrench comes in a variety of products use the penetrating version has a green label and sold at Walmart for sure.Unless the truck needs a good tune up,and the egr removed and cleaned and the exhuast system needs work like the exhuast collector or catatlyitic convertor try the above first.I would however recommend a new set of plugs,wires,cap/rotor button,change your oil and filter and replace the fuel filter,air filter,pcv valve and clean the egr valve under the carburetor with a tooth brush and same chemical and even the oxygen sensor to really clear the system.OK I have owned my 1987 b2200 since new and know this truck.