Hello & Welcome to JA,
These vehicles are very bad on crankshaft sensors, ignition coils (weak) or ECM. I would start by viewing the data from the computer & testing the ignition coils. Check each coil by removing 1 plug wire at a time ,it should shoot a 1 inch spark at least, if not replace it.
No test for crank sensor. With out looking at computer unplugging & replugging sensors is not the way to diagnose this vehicle.
Ignition coils can ohm out good & be bad, spark test is the only sure fire way. Plug wires laying on engine can arc to ground, bad on this engine. I replace a lot of plug wires.
Here is info on crank sensor. you will need special tool to align sensor once installed.
See Figures 1, 2 and 3
The dual Crankshaft Position (CKP) sensor is mounted to the front of the engine, attached to an aluminum bracket mounted to the left side of the engine at the timing chain cover. A 4-wire connector plugs into the sensor, connecting it to the ignition control module. The CKP sensor contains 2 Hall effect switches with 1 shared magnet mounted between them. The magnet and each Hall effect switch are separated by an air gap. A Hall effect switch reacts like a solid state switch, grounding a low current signal voltage when a magnetic field is present. When the magnetic field is shielded from the switch by a piece of steel placed in the air gap between the magnet and the switch, the voltage signal is not grounded. If the piece of steel (called an interrupter ring) is repeatedly moved in and out of the air gap, the signal voltage will appear to go ON, OFF, ON, OFF, ON, OFF. This ON/OFF signal is similar to the signal that a set of conventional breaker points in a distributor would generate, as the distributor shaft is turned and the points open and close.
Fig. Fig. 1: The Crankshaft Position (CKP) sensor is mounted to the front left side of the timing chain cover
In the case of the electronic ignition system, the piece of steel is 2 concentric interrupter rings mounted to the rear of the crankshaft balancer. Each interrupter ring has blades and windows that, in conjunction with the crankshaft revolution, either block the magnetic field or allow it to reach one of the Hall effect switches. The outer Hall effect switch is called the 18X crankshaft position sensor, because the outer interrupter ring has 18 evenly spaced the same width blades and windows. The 18X crankshaft position sensor produces 18 ON/OFF pulses per crankshaft revolution. The Hall effect switch closest to the crankshaft, the 3X crankshaft position sensor, is called this because the inside interrupter ring has 3 unevenly spaced, different width blades and windows. The 3X crankshaft position sensor produces 3 different length ON/OFF pulses per crankshaft revolution. When a 3X interrupter ring window is between the magnet and the inner switch, the magnetic field will cause the 3X Hall effect switch to ground the 3X signal voltage supplied from the ignition control module. The 18X interrupter ring and Hall effect switch reacts similarly.
Fig. Fig. 2: The crankshaft balancer has a series of interrupter rings
The ignition control module interprets the 18X and 3X ON/OFF signals as an indication of crankshaft position, and must have both signals to fire the correct ignition coil. The ignition control module determines crankshaft position for the correct ignition coil sequencing by counting how may 18X signal transitions occur, ON, OFF or OFF, ON during a 3X pulse.
Fig. Fig. 3: Because of their different blade and window configurations, the two Hall effect switches generate 18 and 3 CKP sensor pulses for each crankshaft revolution
See Figures 4 and 5
Fig. Fig. 4: Crankshaft Position (CKP) sensor circuit - 1987-5 vehicles
Fig. Fig. 5: Crankshaft Position (CKP) sensor circuit - 1998-99 vehicles
See Figures 6, 7 and 8
Fig. Fig. 6: If so equipped, remove the crankshaft position sensor shield
Fig. Fig. 7: Position the crankshaft sensor tool on the crankshaft
Fig. Fig. 8: Insert the crankshaft sensor tool into the harmonic balancer
Usually on an engine with Distributor less ignition, when a cylinder has no spark ,it is the coil or module. This engine is sequential fire,which means cylinders fire in order.
Other (some) engines that use DIS ignition will use the "waste spark method". The odd cylinders fire & then the even cylinders fire. power only comes out of the cylinders that have compression & fuel (determined by camshaft & injector pulse). On the Buick engine the cam sensor & the ECM determine which cylinders fire first. This can change dead cylinders on good parts. This problem can be a cam sensor (tells ECM where #1 cylinder is or sometimes an ECM).
No apology necessary . you most likely have much more common sense than these kids today. if changing a part don't fix it ,they are lost. You have a good one.