Pressure gathering in fuel tank

[Ivan141]

I am pretty used to hissing noises from the fueltank in most cars. But I get the impression it's sucking in air as opposed to blowing it out.

Stock fuel pump brackets have a small breather pipe that starts right under the lid of the pump bracket, and then goes somewhere towards the filler neck with a rubber pipe. Easy peasy to make, drill small hole, insert pipe, solder or glue in place. Then make sure it ends up somewhere where it wont make too big a mess if anything comes through.