1989 Other Chevrolet Models carburetor excelleration from st

89chev1500 carburetor acts like choke is closed all the time, no power engine stalls, hesitates on take off. Replaced plugs, rotor cap, distributor cap, air filter, fuel filter, pvc plug, control module for distibutor, still hard to start, engine run fast and slow at idle, after taking off very slow hesitating the more gas you try to give it, then at about 35 or 40mph when you kick in 2nd barrel it will kick in and excelerate very good. It will die when you stop, but restarts good. What is wrong?