You might try some Sta-bil fuel stabilizer in your present tank, first.
That stuff cleans up the fuel system.  I use it instead of injector cleaner,
after a mechanic friend of mine suggested I could 're-vamp' my very
intricate Flat slide racing moto carbs without a complete disassembly by
just running some  clean gas and fuel stabilizer into the carbs and letting
them sit a day or two..Did that and it worked.  Had a clogged injector on my
Ford truck...ran some Sta-bil through a tank and it cleared right up.
  When I got my van, I had missing and some fuel supply issues..First ran in
some Sta-bil, then changed the filter.  Did it one more time, then changed
another filter and all was good...
  I just changed my filter again today along with my fuel lines, and the
motor runs much better...I think I probably had a dirty tank, too, but
changing the filter and using the Sta-bil has cleaned most of the crud out,
I hope...  I have an 1-4 gas motor in mine, too.  Maybe they are more fussy
about fuel pressure, but mine likes clean fuel best, so I'll just change the
filter a few times a year..
  Don Hanson