went for an afternoon drive and car started misfiring and acting like it was going to stall. Pulled over and scanned with a P305 and P1316. Figured since I had a spare coil in the trunk, I'd swap and see if things got any better.

took the coil cover off and noticed that SEVERAL of the leads going into the coil connections were no longer insulated and looked to be making contact with other damaged leads . Looks like time and heat had taken their toll and the insulation had broken off. In the interest of getting back on the road, I wrapped each damaged section with a bit of electrical tape. Any remaining insulation is brittle so I will need to replace the harness soon.

left the coil as is for now and put everything back together, fired her up, cleared codes and drove about 30 miles round trip with no further issues.

Just something for those of us with aging cars to be mindful of. Sorry no pics as I didn't have my cell with me

 

I can speak from experience that that's a great resolution to P030x and P1316 code bundle. Spent months figuring out why I was getting P0307 and P1316. I get what you're saying about heat, age, and plastic, though. It is indeed inevitable.

How many miles do you have on your car, again? I forgot. It's pretty high, right?

 

Currently at 178200.