If any coils were bad, the misfire wouldn't go away with more throttle.

Matter of fact, on the post 2005 2-valves, is there a vacuum-actuated fuel pressure regulator? Might want to check if this is actually hooked up and working. The misfire might be a too-rich condition which clears up with more go-pedal

 

there is a vacuum operated fuel pressure regulator. I saw it yesterday and more interestingly ; many months ago I found the vacuum hose unplugged. I believe I posted it on here (maybe the 1968-2103 van section) when I found it.

I plugged it in and expected changes in engine behavior. I noticed no difference. Strange.

 

Overall I'm mostly looking forward to driving it withOUT the trailer. See how it does.

 

make sure the fuel pressure regulator is getting vacuum at idle - Do you have a schrader (tire) valve on the fuel rail so you can check the fuel pressure easily? If so, it should be 28-30PSI at idle, and 38-40 with the vacuum disconnected.

 

I went back to the Ford dealer to return the coil and I spoke to thE Ford technician that diagnosed my van.
Im colorblind, but he told me the spark plug has a green tip which indicates they were factory installed. He was amazed that they even worked at 314,500 miles. Me too
314,500 miles