P0301 code still

Engine problem 6 cyl Front Wheel Drive Automatic 80,000 miles

I had the P0171/P0174 codes, and before I did some repairs started getting the P0301 code. I ordered a kit to replace the seals, isolator bolts, and valve cover & PCV valve. All that was changed, van ran pretty good. Added seafoam to the tank, started running a little better after that ran thru it. Was still getting an intermittent misfire. Could feel it thru the gas pedal as it backfired thru the exhaust. Loud too. Had checked fuel pressure, and it was about 28 at idle, and would not go above 30 in idle at 3000rpm.
The other day it was raining alot and of course the engine gets some water spray in it, belt starts to squeal. Misfire got REALLY bad and CEL was flashing, and staying on. Had NO power at all below 3000rpm. Wasn't in a spot to stop so I had to keep going. FFWD to today, I scan it and get the P0301 code still, with a slight misfire and random popping in the exhaust.

My questions are the following: would a failing coil cause this? I had a similar issue with a 94 Grand Am, but the misfire didn't show up until the engine was under load and I didn't find it until I started pulling wired with it running to isolate the cylinder (no CEL on that one). I'm not versed on what Ford is using on the 01 Windstar, coil wise.

Other notes as follows:

I've changed the plugs about a year ago, and would rather NOT have to spend another hour under there with my arm in a painful position changing #1 plug 'in the blind' again.

I've read about EGR ports, and I checked a few when I had the upper intake apart. Nothing found with a pick and sprayed a few with carb cleaner. I didn't touch #1 since I found mostly oil residue on the front side (4-5-6 cyl) of the block.

All parts I removed were inspected for movement and grit/dirt and other than some oil on the inside of the intake, there was nothing else (other than the leaking seals, which all were replaced). Should I have dabbed some RTV on the bottoms of the seals?

Thanks for your help :)