As I read your OP, all was fine until you swapped in new plugs and coils. You then got consistent misfires in the no.1 cylinder- that about right?
You then list troubleshooting for everything /but/ plugs & cp's, aside from making the plug gap larger so the cp's would have to work even harder.
I'd strongly encourage trying a smaller gap first like suggested above, then,if the symptom persists, swapping the no.1 & no.3 cp to see if the problem follows the cp.
Not much to go on here, but my money is on the Delphi CP being weak.
Correct, with all the things considered. The first things to check when it comes to a missfires is the most critical pieces to the combustion cycle.
We all know what a missfires is but, there's only a select amount of elements that could be to blame in the process.
Power and fueling are the main to ingredients to make this process work. If your fuel pressure across low and high pressure systems are good then, check the injectors. Common signs of a failing injector is either
A) pull the spark plugs and if they smell like gas or you receive rough starts then you found a problem! (This also lets you see if the spark plugs are okay anyways)
B) in logs you'll notice trends across one bank or both banks that the AFR is deviating from Target either during spool or during high RPM. (Timing corrections may also follow this trend and, you can resolve those possibly as well)
While you have the spark plugs out check the inside of the coilpacks for and debris or corrosion.
If all else fails as mentioned swap the CPs around and see if the trend follows.
Once all of these things are done then you still have some options of things to go trough from bad oil filters causing VANOS issues to possible mosefets failure.
