No spark from plugs. changed plugs, rotor and distributor, cables, and primary coil.

If you take coil wire loose from distributor cap and hold close to engine ground, engine cranking, does a spark jump? If it does, make sure rotor turns when you crank it. The pink wire at the coil goes hot with key on, that is primary voltage, use a test light, is it hot? That voltage comes from ecm fuse1--15 amp, check voltage with key on.
If sensor issue, my first thought would be the crank sensor. Just my opinion.

this generation of gm vehicles is easy to troubleshoot. the engine needs 3 things to run: compression, fuel, and spark. since you mention fire, i assume you have no spark.

disconnect any random spark plug wire and connect the end to a hei spark tester. crank engine and observe for spark. if you have no spark, disconnect the center terminal of the distributor cap and use the hei tester in the same manner. spark means cap and rotor bad or bad plug wireset. no spark means make more checks.

check for battery voltage and good ground on distributor. check for open or shorted ignition module or ignition coil windings. if power and ground is present and ignition coil tests ok, check for ignition pulses at coil primary. if you have no ignition pulses feeding the coil, change the distributor.

with that generation of vehicle, the ignition system will operate without help from the computer. don't even troubleshoot the guts of the distributor, if you change the cap, rotor, and anything else, it will be the same price as a remanufactured distributor, and might not fix the problem. if you troubleshoot a low volrage related issue (no pulses, shorted or open circuit, unstable timing, etc), change the whole thing.

Do you mean you can take off the coil to dist. high tension cable at the distributor end, and you get spark from the coil? If the spark is strong and blue, then the only thing between that and the spark plug wire end is the distributor cap and rotor. Both are high wear items, good to replace them every hundred thousand or two. Miles, that is.

An ignition system has a primary and a secondary circuit. The secondary circuit is the high voltage coming out of the coil to the top of the distributor, where it touches the top of the rotor, and the current is passed from the center of the rotor to the tip, where it whisks by the metal tip on the dist. cap where a spark plug wire connects. So a continuous current from the coil to the individual spark plug wires, and to the plugs. It's only an instant, but it's a current flow from origination in the coil to ground. When the current reaches the bottom of the spark plug, it has to jump a gap to find a ground. When it jumps, it conveniently makes a spark.

Start with the ignition coil. It should have power to it with key on. Should be battery voltage on the primary circuit to the coil-that's the coil positive terminal. If the coil is good, it could be a bad ignition module-the module cuts primary current to the coil when commanded by the engine computer.
It could be several things-fouled plugs, bad plug wires, cracked distributor cap, bad rotor, crank sensor or pick up coil (inside the distributor), pcm. Test the ignition coil, or try a known good coil.

If you can tell me what color the wire is I should be able to tell you where it goes.
But if you are getting spark from the coil tower the primary ignition system is working.
Have you checked the coil wire, and will it fire a plug ? The coil could be weak enough to fire a plug in open air but not in a cylinder under compression.
You do know for a fact the distributor rotor is turning, right ?

Check all fuses under the hood. Test the coil with an ohmmeter. Check for battery voltage on the coil primary with key on.
If all good, suspect the crank position sensor. A bad sensor will cause no spark.

I guess you could have the ignition analyzed on an oscilloscope. Maybe a tech could see something then.
I always heard the only gap was the spark plug gap-the rotor has no gap-are you sure you got the correct rotor? And does it touch the top distributor cap coil wire tower?

Let us know. It is a mystery worthy of a solution.

Replace the distributor cap and rotor. If you have fire from the coil but not from the distributor cap, you have a bad contact point between the cap and rotor. Replace both and you should be good to go,, if the information that you have supplied is correct.

1 remove the cable from the coil to the distributor.
check this agains earth, when you turn the engine over.

if spark, suspect rotor arm is not setting spark to each spark plug lead.
open distributor and clean the rotor arm with a cloth or wire wool
not sand paper as this will take off too much and cause a problem

2 check inside distributor for moisture. spray inside with WD40 or equiventy water repelent.

3 if not spark at coil open distriutor cap and with ignition on, open and close points in distributor with a screw driver and check coil again against earth again if you get sparh, problem is points not opening and closing.

4 turn over engine with distributor cover removed to see if rotor arm is moving if not then cam drive to distributor is defective. this controls points and rotor arm.

if rotor arm turning and spark at points but no spark at coil suspect Low tension wiring or coil needs replacement.

i hope this was helpful

think this could be factory immobiliser ,try spare key if still no joy dealer only