2003 Savana fueling problem

When I go to the gas station to fuel up, I insert the fuel nozzle and as soon as I squeeze the trigger it trips off as if the tank is full. It does not matter how I position the nozzle or how far it goes in, it immediately trips off. I have tried many gas stations, no help. The only way I can get fuel into it is if I pull the nozzle ALL the way out of the fueling receptacle and barely & ever so slightly squeeze the trigger and basically just let the gas trickle into the tank...literally. The very instant that I insert the nozzle back into the tank..it trips off. It takes FOREVER to fuel this thing. I removed the fueling neck all the way down to the tank and the coupling hose. No obstructions, everything looks perfect, it's quite puzzling. I can stick my finger into the actual tank opening and feel a spring loaded poppet valve, it's not sticking and operates with just a small amount of pressure. Reassembled everything, no help. Thanks in advance for any advice, I do appreciate it.