Whenever I go to the gas station, I always fill the tank up. Normally it auto stops.

There's been a few times when the pump stops when it's clearly not full. I tried pulling the level again, and it stops within a few seconds as if the tank was full. When I start the car, it's only about 1/2 or 3/4 full.

Any idea what's causing it?

 

Sounds dumb, but try backing the pump nozzel out a tiny bit if it does this next time. It might take care of the issue. If not then I'm not sure what to say.

 

I never try to top it off more than 1 click....i've had it spill out on the 2nd attempt....but never had it be 1/2 full. Does it do this at ALL gas stations? I'd guess on a faulty pump

 

This

 

I'm going to try what BerlinaBlaster suggested. It only happened to me a few times in the last 2+ years that I've had the car. Never happened with any other cars I pumped gas for either.

 

I've seen it happen to my car twice in 4 years.