To update this... I found out that plastic connector box is called an "ignition coil".
I purchased 3 on amazon for $50 total including next day delivery.
Will be replacing all 3 coils tomorrow hopefully. Also, spark plugs.
Since I'm only working on the passenger side, I might just replace those...
So my truck is a 1995 T-100 with 200k.
Started running really rough. Oil level was fine.
Turns out, it's not running on one of the cylinders because a spark plug connector was melted!
Here are attached pictures. Can someone tell me what parts I will need to fix this?
Looks like the underside...