89 S10 blazer timing

I have been through hell and back on the timing. I unplug the tan wire with black strip under the heater box and then align the second mark on the damper at 0 and the first cylinder is at TDC on compresson stroke. Now I think I messed up removing the distributer, but I have it back with the rotor pointed to the #1 spark plug and everything still at TDC. I start it and check the timing with a gun and then shut it off wait 10 seconds and plug the tan/black wire back together and start the truck back up. It will run at the usual high RMP for 15-20 seconds sounding just fine, but then it back fires and dies. I thought the distributer was a tooth off, but it looks like it is back where it was for the 10 years I have had it. I have always been able to fix it over those years, but now I do not know what to do.
PLEASE HELP ME,
Thank you,

Sounds like you have the base timing set correctly, and it's time to start investigating the EST system. Make sure the detonation sensor is connected (on the right side of the engine, just above the starter). Make sure the connectios at the distributor are intact - Not just plugged in, but clean and conducting.

Does the "CHECK ENGINE" light remain lit while the engine is running?

Sounds like you have the base timing set correctly, and it's time to start investigating the EST system. Make sure the detonation sensor is connected (on the right side of the engine, just above the starter). Make sure the connectios at the distributor are intact - Not just plugged in, but clean and conducting.

Does the "CHECK ENGINE" light remain lit while the engine is running?

The check engine light only comes on while the tan/black wire is unpluged, then goes off when I shut the truck off and plug the wire back up. I have installed all new wires, plugs, dis. cap, rotor button, O2 sensor, fuel injectors, coil, control module, and some more things I can't even remember.
I believe all connections are good, but the spark plugs did get black and I changed them again. Now they might be black again, but I will change them again if I can find out what else to do next.
Thank you so much,