Ever since I've replaced the sending unit and pump, the gauge has been way off. I don't know if I shorted the wires to the gauge and messed it up or if it needs adjusted or what. But If I put 20 bucks in it, it goes up a little over E, when really it ought to be a bit over a 1\4 tank. Then it sits on E for the last 80-90 miles in the tank. I might have messed up the gauge somehow, because the plug for it rotted out so the wires are clipped on the pins and they could have shorted out when I had this disconnected but im not sure.
Any ideas?

 

Probably the float arm was bent wrong when/before you installed it.

 

Do you have to bend it when you get it?

 

How would I go about adjusting it?

 

You will have to pull the pump from the tank and from what you explained , straighten the arm on the float so it sits closer to the bottom of the tank when empty.
If you still have the old pump assembly laying around , you can see how the float , when fully down , should sit just above the intake screen.

 

I used to have it sitting around, I didint think i'd never need it so i threw it away.
Damn it