not sure if you have found the problem yet but One truck i had worked on before had no action from one coil. these coils use battery positve, pcm control and also the low reference signal. it can full you checking the low reference because it wont light an ordinary test light if checking. you need a meter to see if its getting voltage there. im guessing you already knew that, just thought id throw that out there.
So it was in fact getting spark this whole time?? With all the coil changes, and other checks, did you actually check for spark, or just assume there wasn't any?
a guy i had working on it said he did check for spark y pulling the spark plug and grounding it but in fact he didnt. i got tired of him messing with it and went and picked my truck up. and that was first thing i did and it was getting spark the whole time. he also said he checked the compression but he didnt do that either. i checked it after saw there was spark and it showed zero compression. took off heads and the piston was bent open and after further examination the valve guide had cracked causing the valve to stick and piston hit the valve bending it. thats what happens when get impatient when injured and not able to work on my own truck and get someone else to do it thats lazy.
Well that just sux. At least you have a definitive on what the issue is.