92 S-10 Blazer 4.3 Vortec Looses Power off and on?

I have a 92 Chevy S-10 Blazer 4.3 V6 Vortec 4X4. A few months back while driving my blazer just died. I was unable to get the truck stared and towed it home. I replaced the Plugs, Wires, Bug, Distributor Cap, Pick up coil, and the Coil Pack. I then took it to a mechanic to find that the fuel pump went bad. Had the mechanic replace the fuel pump, the fuel filter and found that is was 50 degrees off time. Since that day I have had power issues. To resolve the power issue I have replaced the TPS sensor, CPI Spider Injector, Ran diog on the Ignition Module, did a back preassure check on the catalyitic converter, replaced the compluter, replaced the PCV Valve, checked for vacum leaks, and checked all the grounds that I know of. My power issue still remains. Symptoms of my power issue started off like so. I start the trunk up for the fist time in the morning to let it warm up and once I take off the trunk has its full power. While taking off from a stop after about 5 minutes after intial start the truck will just loose power. I can feel the power and the trunk just fall back. This will stay like this for the rest of the day. I find this issue to have changed in that it is off and on now through out the day. Sometimes I will have full power then sometimes I will not. A new issue after replacing all of these parts is for the first start of the day the truck will start slugish and die. I restart and it will idle rough and eventually leverl off at a smooth idle. This symptom is also an on and off issue. Sometimes it will start right up and sometimes it will die on the first start. I am at the end of my rope and need help. If anyone has any idea please let me know.