Never underestimate the power of a new fuel filter... And use a bucket..

 

Yes!! I think every Mustang or truck I've bought had clogged or nearly clogged filters. I replace them every 2 years regardless of mileage. Fastest way to kill a fuel pump, low fuel pressure at WOT is a dirty filter!

Also, pull the pump fuse next time, start it, it will run out very quickly. You'll still get some spillage, but not as much!