90 gmc sierra no start

you need to change the point distributor , but before that check the cable from coil to your distributor .

replace the ignition module or pickup coil located under the distributor cap ignition modules work when cold and will stop firing when they are warm when they r going bad

Is the EFI spraying gas or dripping gas by anychance. I blowed a o-ring at the base of the injector on mine and did that to me.

First make sure your coil is good also your ignition module your crank sensor will also cause a no spark situation start with these let me know something.

The distributor cap and/or the ignition rotor most likely have a crack somewhere and the distributor cap should be replaced along with the ignition rotor. The ignition module could have been damaged as well as the ignition pick-up coil/stator and if replacing the distributor cap and ignition rotor does not solve the problem then the ignition module or the pick-up coil/stator assembly inside of the distributor is also most likely damaged and the distributor will need to be replaced. There is a certain procedure for removing and replacing the distributor, and the ignition timing is not adjustable and it is not set using a timing light or with the engine running, and if you do have to replace the distributor Let me know if you require the procedure to properly remove and replace the distributor or if you require any further assistance.

pick up coil in the dist is weak

Sounds like fuel pump

Doesnt this engine use a crank position sensor? mounted on timing chain cover.I would check that first

I had the same problem with a GMC s-15 Jimmy changed the distributor and it has not done it since

no codes. most direct components changed.
computer. take it out or have the truck towed to the shop/dealer to test the computer.