I had a similar issue but cyl #4, pulled the plug and noticed the plug gap was right at .084" instead of .060" 😳🙄 lightly sanded the electrode reinstalled problem was found, New set of plugs are now in there 🙂
Related to what has been said, check the sparkplug first. The #3 plug is harder to get to because it's behind the steering shaft. I had a used S10 and discovered someone had previously changed the other 5 plugs, but not #3. It was still original after 125,000 miles.
If you do change your plugs and wires, go with OEM (sparkplug: ACDelco 41-993 Iridium, not sure on the wires part #). Rock Auto is a good source for them.
1.) Use a volt meter to check resistance on your wires going from your distributor to your spark plugs
2.) Are your spark plugs dirty or fouled up?
2.1.1) If so is it oil or a injector stuck open
2.1.2) to confirm it's not oil do a cylinder compression test, and wait 10-20m to see if it holds the compression.
2.1.2) Once you covered all topics put all new spark plugs in.
3.) Check distributor for corrosion or just replace it.
*Also a stuck open injector would cause slow shifts or rough shifts. And if you think your spark plug looks black. It may be gross gas. *