Hey guys this is my first post here, but im hoping you guys can help me figure out a few problems possibly related somehow?

My truck is a '93 Explorer with 294,400 miles on it. It just got a new tranny and now im noticing a few issues with it. First of all, on hot days, the gas tank seems to be building pressure. Im talking, open the gas cap and all sorts of pressure / vacuum happens...you can see the vapors escaping too. So thats issue number one.

Issue number two is that when I do hot restarts after letting the truck sit for at least five minutes, the truck seems to run on 5 cylinders, but it clears up with a bit of revving and then it runs fine. It wont do it cold either. To me it seems that something is heatsoaking and messing up. Could it be a fuel injector or the coil starting to go?