Since I have owned my 87(Little over a Year) I have had this problem when I start the engine. In them morning when I first start it, it will crank over real strong but when it fires up it is real sluggish for about 5-10 seconds and I get alittle bit of black smoke out of the tail pike. Then the idle goes up and the black smoke is gone. It will also some times make a deep pop,pop,pop noise out of the exhaust when I let of the gas after reving the engine while in park(not sure if there is a relation). The exhaust also smells pretty bad when the truck has been running for awhile. It is also sluggish going up hill. Now I have been told that the smell and the black smoke are from running to rich. So what I have done was replace just about every senor under the sun in the last year(O2,MAP,Temp,EGR,ECM,PVC,Knock,TPS,). I have also had a injector replaced, the heads redone, cat and muffler replaced, trans rebuilt, new batterie, ignition module, pick up coil, ignition coil, cap, rotor, wire, plugs, k&n, fuel pump has less the 20000 miles. The timing is also set at 0 degrees. So, I come to you guys for help. I need some suggestions. Maybe I am over looking some thing very small an not realizing it. Thanks for any help.