90 chevy 350 tbi crank no start, truck was started driven around the block parked it and let it idle a few minutes before shuting it off, the next day it would not start, it acts like timing is off and is backfiring through the throttle body, I have checked the timing it is dead on. the distributor had some corrosion and rust inside so I replaced the distributor (including the reluctor coil, cap, rotor and ecm) I had recently replaced the coil, plugs and wires. It has spark, fuel, and compression Im lost.

Lost me there at"injectors don't fire, but they do" Anyway, the crank sensor/ECM is what controls injector fire. Could be corrosion at the injector,crank sensor, or ECM plug. Could be the injector/s died. Been a long time since I worked on a TBI. but the injectors can be checked with an ohm meter. I don't remember the numbers though. You can find the numbers on the internet.

Could also be a problem with the throttle position sensor

vacuum lines

Sounds like the fuel pump is going bad(or in this case,has gone bad). I suggest that you change the fuel pump and use a fuel cleaner in your gas tank as dirty gas may have caused the problem to begin with.

Have you checked Google I found this hopefully it's not your timing or it may be flooded but doubtful have you tried spraying starting fluid into the intake while cranking it

I have a 90 chevy k1500 350 tbi with same problem! I have traced problem to... after turning on key fuel pump kicks on when u crank it over injectors shoot gas and truck starts! After few seconds injectors stop spraying and truck dies! This can happen many times over and over! Eventually sometimes truck stays running and all is great! I changed ignition module, oil pressure sending unit (which i was told controls gas after vehicle is running) fuel filter, computer, fuel pump relay, I am at a loss now! Hope this helps and hope someone can help me!

Sounds like a poor idle. try adjusting the idle screw.

Sounds like fuel pump is failing

check if went from a V6 TO V8 need power two more cylinders