So that last run you were freeway speeds when it overheated.
I don't trust what Pep Boys told you, I haven't had much luck with their work in the past. Did you see the fan running? You said it had more than one, AC and it stayed cool with the AC on?
22 gauge is way too small, its best to use 16ga for the fan, 20ga.
I'm still thinking fan, could still be thermostat (sticking), slow leak only under pressure, weak cap, or even a bad pump, I saw one that would work for a little, then quit for a little. Is there any smoke coming out of the tailpipe, have someone follow you, and what color is it if it is.
My wife had one where the ECU quit giving the command to turn on the fan, unless the AC was on.
After doing a bit of research it seems that the most likely culprit is actually the head gasket is starting to fail, it has been talked about in a few forums as starting off with what you are experiencing.
https://www.civicforums.com/forums/3...reference.html