Gas guage always reads full, except when sitting still then drops to empty. Check Engine light stays on. Computer reading said it was fuel pump? If so, where is fuel pump located?

Check that there are no holes in the float. If the fuel is getting into the float, it will give a false reading. Another thing is to check the ground on the float sensor. If it's not connected tightly, it will create a false reading too.

It sounds as if the fuel tank sending unit is faulty. This is a small float connected to a variable resistor on the fuel pump/sending unit assembly. Unfortunately this assembly is fairly expensive (over $300) and the fuel tank may need to be removed to replace it.

just replace my fuel pump /sending unit on my 06 Malibu, didn't matter if the pump was in or out of the tank, the gauge still reads wrong

sounds like you need to change sending unit in the gas tank

Have you tried disconnecting negative battery terminal for minute or so? Helped on my 2003 malibu once

It could be a bad fuel gauge in the dash unit, but....
Usually it's "The bad".
The fuel level sending wipe arm and windings on the fuel sender wear and send erratic readings.The only cure is a replacement fuel gauge sender.
The check engine light should not be related to the erratic fuel readings.
"The good".
If you have over 200,000kms or 120,000 miles on your van you need a new fuel pump anyway,so have a complete assembly put in which will have a new fuel sender on it.

You most likely have a failing fuel level sending unit which is located inside the fuel tank. The sender wears a bit as the float arm moves up and down with normal fuel level variations and this wear can result in a guage that reads erratically. Many of the fuel level senders are now only sold as a part of the fuel pump module so if it turns out that it is indeed the sender you may have to replace the entire pump module. Hope this helps!

sounds like fuel pump is good the floater may need replacing or the wire that reads the floater may be loose

It is most likely your fuel level sending unit has gone bad. It sits inside your fuel tank to tell the fuel guage how much gas you have in the tank.

The sending unit for the gas gauge is in the fuel tank and part of the fuel pump module, it is not sold seperately. Price is around $350.00, 2 hours labor to install the part.

MAYBE THE PROBLEM IS IN THE TANK PROBABLY THE CIRCUIT ATTACHED TO THE FUEL PUMP THE ONE READ THE FUEL IN THE TANCK IS GOING BAD