P0300 Requesting Advice

[Hair]

SOLVED!!
I replaced the Cap and Rotor Button and it fixed it!!
Thank you guys for recommending that I try replacing those!!
Y'all were right!! I would have bet $10,000 that was not the issue.
When I pulled the plugs out and started it, fire would jump two inches to the manifolds. There was no way that I thought that fire was the issue, but it was, the cap looked corroded and the rotor was a little burned on the end. I put in new Cap and Rotor and blew out the vents (they were not stopped up) and only #5 was showing a misfire. I pulled that plug out and hit it with a wire brush. fired it up and BOOM! No code and no misfires on the scanner!! That #5 plug would have probably cleaned up going down the road, but anyway, I'm good now and thank you guys so much, because I was within a hair of buying intake gaskets and a new fuel spider and spending my Christmas break on that.
One last note for future people: Back when I was trying to figure out what was wrong, trying to diagnose, another thing I noticed, #3 & #5 at the manifold would never get over 200 degrees and all other cylinders were about 400 degrees. That could have been a weak spark that made that difference. IDK, but I'm glad I got my truck going again. Thanks Again guys!!