1988 Chevrolet Silverado K1500 4X4 problems...?

I just bought this truck. It has 150,000 actual miles. It has been in storage for the last 5 years. When I first bought it, it ran great. Now after 900 miles, it shakes at idle, misses at idle and after idling for about 4 minutes, it smokes like crazy. Blue. Give it a little gas and it clears right up, both the idleing and the smoke. I am getting 11 mpg highway as it is. 350 TBI motor. I have changed the plugs, wires, cap and rotor but nothing different... Any suggestions would be greatly appreciated.