1995 GMC Pickup Won't Start After Sitting Over Night

Is there a tach place on the distributor cap? If so, use a test light on that terminal, engine cranking, see if the lite pulses? A pink wire should carry voltage to coil or distributor cap. It goes got with the key on? Use a test lite and check for voltage. A couple of possibilities, check the ignition module and pickup coil in distributor. Does the distributor rotor turn when you crank it? With gm bypass ignition, it's the ignition module that controls spark during cranking rpms, not the computer.
There is an oil pressure switch in the fuel pump circuit, so once you crank it enough to bring up oil pressure and that switch closes, the fuel pump will run even w/o a rpm signal, but, for other components, the rpm signal is important.
The ignition module gets signal from pickup coil, engine cranking, then ignition module sends rpm signal to computer on purple wire with white tracer. If no signal, the computer won't ground the fuel injectors, among other issues.

Sounds like the coil or wire.
Engine running squirt water all over the coil and wires and see if stalls.

Sounds like you have several problems.
If the engine will not crank, do you have power on the purple wire on the small starter terminal when the key switch is in the start position ?

Have you ever heard of testing before replacing parts ? Fuel pressure an flow tesing , testing the electrical circuit for the fuel pump , amp draw testing , voltage drop testing etc... Thier are no magical fixes in auto repair . No spark ! check B+ voltage an ground circuits for the ignition system , Ignition System Designs Operation and Testing an SD Premium video

CLEAN FUEL INJECTORS.THEY ARE FLOODING THE ENGINE.WHEN YOU TURN OFF ENGINE DIRTY CLOGGED FUEL INJECTORS WILL KEEP LEAKING FUEL FLOODING ENGINE.ALSO REPLACE AIR FILTER.

Here's one thing you can do, carry little gas with you and when it cuts off, pour some gas down the intake manifold or throttle body. If it starts you probably have a fuel problem. If it doesn't start you most likely have a ignition problem. Using a test light check for Power going to your coil or coils. To rule out the ignition switch. But if I were to take a guess, ignition coil or coil wire, and if it has a distributor, ignition module pickup and rotor. Good luck.

check the ignition control module wires are shorting out? Try the wiggle test next time no start. wiggle the wires and see if it starts.This is a factory mechanic approved test procedure.

May be fuel related or ignition related:

Fuel: Obtain a can of "starting fluid" from an auto supply store. Spray directly into air intake for two seconds. If car "kicks" and trieds to start, then the problem is fuel-related. If you spray more, then it may start.
Could be: Fuel filter or fuel pump.

Ignition: Remove a sparkplug cable and lay it down on a metal part of the engine. Have someone crank the starter while you look for a spark from the cable end to the engine. If no spark, it could be several things:
distributor rotor, distributor cracked and/or wet on the inside, ignition coil.

When you say "cranked but would not turn over" I assume you mean it turned over but would not crank. Otherwise, it does not make sense.

Assuming that, I would replace the fuel filter. It is a cheap part and easy to install. What happens is dirt gets in the filter and stops the car because it is not getting fuel. After sitting a while,the fuel dains out of the filter along with the debris and it works well until it happens again (usually when you are low on fuel). It is a cheap fix and probably will solve your problem.

1 Inspect Battery Damaged or faulty battery and/or connections. here is a list of things u can check hope this helps Shaun 2 Inspect Coil - Ignition Damaged or faulty ignition coil or ignition coil circuit. 3 Inspect Fuel Filter Clogged or dirty fuel filter 4 Inspect Fuel Injector Pressure Regulator Faulty fuel injector pressure regulator or circuit. 5 Inspect Fuel Pump Improperly functioning fuel pump or circuits. 6 Inspect Wireset Damaged, worn, or deteriorating spark plug or coil wire(s). 7 Inspect Control Module-Ignition Faulty ignition control module or circuit. 8 Inspect Solenoid Switch Damaged or faulty solenoid switch or solenoid switch circuit. 9 Inspect Starter Damaged, worn, defective, or faulty starter or starter related circuit. 10 Inspect Neutral Safety Switch Damaged or faulty neutral safety swittch or circuit. 11 Inspect Fuse Corroded, burned, or shorted fuse may be interupting power source. 12 Inspect Fusible Link Corroded, burned, or shorted fusible link may be interupting power source. 13 Inspect Battery Cable Corroded, broken or poorly connected battery cable. 14 Inspect Spark Plug Wire Loom - Performance Improperly adjusted or worn/malfunctioning carburetor. 15 Inspect Distributor Cap Loose or cracked distributor cap 16 Inspect Distributor Cap And Rotor Kit Loose, cracked, or worn distributor cap and ignition rotor. 17 Inspect Fuel System Pressure Incorrect fuel pressure being delivered to carburetor or fuel injection system. 18 Inspect Fuel Injector Plugged, dirty or poorly connected fuel injector. 19 Inspect Ignition Switch Worn, damaged or faulty ignition switch or circuit. 20 Inspect Spark Plug Fouled, damaged or broken spark plug(s). 21 Inspect Belt Incorrectly routed, adjusted(tensioned), missing or worn drive belt(s). 22 Inspect Timing Belt Slipped or broken timing belt. 23 Inspect Timing Set Slipped timing chain or worn timing gear(s). 24 Inspect Fuel Tank Contaminated fuel from rusted or deteriorated fuel tank. 25 Inspect Ignition Timing Incorrectly adjusted engine timing.