Someone tried siphoning gas out of my friends Express. Luckly they didnt get any but now it takes a while for him to pump gas into the tank why?

 

Probably clogged up a vent somehow. I have the same problem with my van. Depending upon the pump nozzle, it will keep shutting off. So have to pump at half pressure... takes an eternity. I have tried every trick in the book to remedy this. Even blew out the lines. Dealer "can't duplicate the problem".

 

remove the filler neck and make sure its clear. some vehicles have a roll over ball at the top tank where the filler neck attaches. the ball would block the siphoning attempt but may also slow filling if not seated after they pulled the siphon hose out.

 

^ I agree...
(they have screens in 'em to prevent siphoning anyways haha)