Hey my 1990 4.9 it's not telling me how much gas I got in the tank, when I put in gas I have to do it slowly if not it will pop the gas gun, what is the problem?

 

I have a 1980 F150 with the 4.9 in it. It does the same thing, I have to hold the gas gun with the end just barley in the fuel neck or it will kick it off after a few seconds.
My gas gauge had been stuck at empty for a long time, than it got stuck at full, It turns out that the new sending unit I got from LMC was dead out of the box.
If you unplug the wires from the sending unit does the gauge drop to E?

 

I will locate it later today and unplug it to see what happens

 

Where is it at?

 

It is on top of the gas tank. Mine is a rubber plug with two connections in it that just pops off. Yours may be a plastic type connector that you have to pop off with a screwdriver

 

I dont get it. You watch the fuel gauge to tell you when its full when fueling up? If its a pain to fill because it pops the gun all the time this has nothing to do with the gauge. You just need to slow the fill down or try and find the correct angle that the filler neck likes. Certain pumps fill faster than others. I have this problem at some stations and not at others. As for changing your sending unit, yeah, what they said.