Sounds like the ignition MODULE is bad. It is mounted underneith the distributor cap and it will be on the right side of the distributor plate. Go buy a new one and when you take the cap off you will no what to look for. There's 2 small screews that hold it in place and the electrical wires just unplug.
Does it have fuel, spark (BAD COIL?) and compression?
It takes 3 things for the engine to run. Fuel, spark, & air. You have air, and the truck turns over so you are missing either spark or fuel. You have to find out which of those you are missing.
first check to see if your getting spark, or fuel
1990 ford truck no spark
make sure its not getting to much fuel and check the timeing/and if the wires are in the right order
A bad spark plug, spark plug wire, distributor cap, rotor, fuel injector or burned valve.
make sure it's getting fuel and make sure it's getting spark to the plugs.
* No gas * Clogged fuel filter * Malfunctioning fuel pump * Spark plug wire * Voltage regulator problems (not allowing enough voltage for spark)
I would replace the ignetion module that is in the distributor.
every engine needs fuel, air, and spark. which is it not getting?
I would start at the fuel pump if it is getting fire and will only run with fuel squirted in throttle body i would see if your fuel pump is working before i tore into it i would try the relay .
Assuming you replaced the fuel filter, here are a few things to check, Spark plugs, Spark plug wires, Distributor cap and rotor,