1988 Chevrolet Blazer idle up and down

The truck idles up and down in park and won't stay running in gear without using accelerator. Truck has new gas tank, fuel pump, fuel filter, idle air control valve, ignition control module, distributor, distributor cap, rotor, spark plugs, intake gasket, vacuum lines, and map sensor. The truck will run perfect in park with the map sensor unplugged. And will run in drive and reverse perfect at idle put when u accelerate it has no pick up or power. With the map unplugged. Have checked timing and firing order fuel pressure and compression. And all check good. Checked all vacuum lines rebuilt throttle body changed injectors. Still the truck will only run with map unplugged. Please help.