When getting gas the pump is forced off like the tank is full when its not.

I have a 2010 Impala and it is the way you are putting that nozzle into the fill hole, too far and it will kick off, back it out a little and start off slow.

Probably an issue with EVAP system. When you put gas in, the air and fumes must be displaced... the fumes do not just go in to the air, but through a charcoal canister to be held until the car is started and the the canister is purged back through intake. So could be blocked vent line..... purge solenoid This is generic not specific to your Impala but they are all the same

Good info Rowefast

I always readjust the pump by moving it around and backing it out and still have these results of shutting off like the tank is full. What gets me is the 3 different vehicles have done this. This doesn't happen with our Ford F150 or my Dodge Avenger and it happens to anyone that fills the tank. So is it still possibly a block even if its happened to multiple Impalas?

Well, I do know Rowefast knows what he is talking about. Mine is a guess. I am more of a Toyota guy than GM

But I must admit to being puzzled by this happening. It's not like we get a lot of questions on this happening to Impalas

I think it is all in technique myself, like you say 3 Impalas have done this? But who knows... Like FordNut suggested to have the EVAP system checked, cleaned, it could only help.

Try holding the pump handle upside-down when filling up. This works like a dream for me. I was strutting around like a Cocoa Beach peacock when I figured that one out.

My 2002 Chevy Impala does the same thing where it shuts off the pump like it's full.