Car won't start...it cranks but won't fire.Had coi and ignition module checked both good. Bought the pickup coil and still won't start! Why won't it start?

check for codes, if there is one it will help to know were to start diagnoses. it could be crank sensor. check for power and grounds at the coil and ignition module. just some place to start.

Do you have battery power at the coil when the key switch is on and when the engine is cranking ?
The rotor on the distributor is turning, right ?

Yes the crank sensor could keep the coil from firing, but your truck does not use a crank sensor assuming its a V8.
The coil gets power from the key switch, and the ignition module inside the distributor grounds the coil to fire it.
So the problem could be the coil, or the module or pickup in the distributor. The pickup coil in the bottom of the distributor acts as a cam and crank sensor.
You may need a repair book or shop manual to get the test procedures.

Check for spark at any of the sparkplugs.If there is no spark at the plug then replace the distributor ignition pickup coil.

If the coil and ignition module are good then check/replace the ignition switch.

Maybe a broken wire going to the distributor, Check that first. Check fuse also ( Engine fuse ). Check distribution box ( brain box ).

If you have no spark, chances are it's the TFI ignition module. To narrow it down, turn the key on. The check engine light should be on. Now, crank the engine for a couple seconds while watching the check engine light. If it goes out while cranking, the pickup coil is good and the signal is reaching the processor. Most likely, this means it's the ignition module.

check wires an plugs also

Have you checked the cam sensor. It coincides with the crank sensor to tell it to fire . And it controls the injectors.

This unit has a pickup in the distributor that tells the coil when to fire. Check to see if you have power at the coil. If yes,connect a test light to the ground side of the coil and have an assistant crank the engine.The test light should flash on and off. If not, you have a problem inside the distributor. The pickup coil or the ignition module are at fault. Good Luck