I have a 1988 4.3 liter v6 and the oil pressure gauge is messing up and both back speakers do not work. I wonder if this could be from blown fuses? There are two that are not even in there. Anyone have a pic that tells what ones do what?

Your speakers can be checked with a battery. Attach + to + and - to -. If the cone moves the speakers are fine. On the back of the fuse box door should be a diagram of your fuses. I do not have one handy.

Oh, on your oil pressure check your oil pressure sending unit. It could be bad.