Don't know about the methol hydrate.
Don't worry about #4 if you don't have an adjustable regulator.
Clean and regap the plugs, and clean the contact points inside the distributor cap, and the rotor tip. Make sure the plug wires are separated from each other, and are firmly on the plugs.
I'd spend at least a half hour driving around on your way to get it tested. The hotter your exhaust, the better the cats work.
Take care,
~Chris
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