I had a mishap at the gas pump

[fourfourto]

I was filling up on the way back from camping and I had the pump running as I was cleaning windshield(the pump had a lock clip I didnt wedge something in there) and it didnt stop when full and started to overflow all over the back of the truck. It must have put a couple of gallons on the ground.
Then the truck started to run rough and black smoke came out the tailpipe and then it stalled ?(yes I had it running as I was pumping gas)
It started back up a moment later and alls fine ,I saw a hose next to the office and hosed it down good.I also went inside to tell the guy so he could clean it up and he gave me a look because he had to get off his a$$.I wasnt in the mood to confront him about the couple of gallons I lost ,I was more concerned about hosing down the rig.
If he was pumping and it happened I would of had a $hit fit.

It must have backflowed into vent tube ,also it took a moment to settle down the fill tube.

This had never happend to me even if I wedge something in there, good thing no one was smoking