Welcome aboard.
Fans can run but not be at full speed when the motors get old. One is single speed, one is multi speed, at least in my understanding of it. Different prices when I've bought them. Anyway that will make it run hot at the drive thru. Some advanced scan tools can monitor fan speed. I'm not familiar with test procedure on the motors but you did say the word sluggish. They could be switching on properly just not moving enough air.
I've had the firing order wrong on mine for long periods, a couple different incorrect ways. Some may say it won't run that way or run terrible... but it ain't necessarily so. I know. If you haven't removed the ICM from the vehicle I suggest that you do, for cleaning of the area. It grounds to the engine there. This allows a close look at the little clylinder numbers on the ICM to eliminate doubt of proper plug wire position on that end, while you're there.
New plug wires often have crappy terminals, double-check those. Just throwin in more ideas to confuse, lol.
