Spark plugs and air cleaner filter

Remove the spark plugs one at a time. Use a thin file to clean electrode, then regap and install.

.O60 gap for spark plug. The autostore has feeler gages for the spark plug gap.

They actually need to be sand blasted. They make a small tool that does just that but you may not find them readily accessible. Unless you get the porcelain cleaned and white again, you're still going to have problem. I have done it in the past using a small but hot torch and getting the porcelain red but don't let it crack.

That's a subject for a new question.

Does the fan run when you turn on ac? Does the fan run if you use jumper to access mil codes? Some GM models, doing either one will cause the fan to run. Any mil codes? You could take connector loose from fan, use jumper wires for voltage and ground from battery, see if fan will run. Use inline fuse, just in case.