Isnt the fuel tank cap supposed to be vented ? Unless mine sets overnight it has a vacuum in it when I remove cap to refuel . I would think this would be hard on the fuel pumps.

 

You would think it would, however I know a couple people that have fuel from an auxillary tank that gravity feeds into the existing truck tank. They said it never leaks as long as you put the cap on the truck tank until it clicks.

HTH

 

Mine done this also, I replaced it with one from Walmart (Stant I think) for $12, it is the locking pre vented fuel cap, I never hear a woosh when i go top open the cap anymore, and no more 3rd gear starts.

Clint