<p>Hank already knows where Jesse lives and that Saul Goodman is his lawyer and that Jesse is in trouble and needs legal counsel. He also already had people watching Jesse.
</p><p>As for where the meth came from, Jesse cooked tons of it during the duration of the show, it's not improbable for him to have kept a stash around considering how often he used it.
</p><p>And ditto to
Madrigal-Ehrmantraut, every gas station sells gas tanks, and most homes with cars I've been to have one in storage. If that's a plot hole, that'll be like saying any prop that's not previously given an origin is a plot hole. <i>Where did the vending'
machine in the car wash come from? We never saw it before it was in the A1A Car Wash.</i>
<i>Kind of contrived how it's just there right for Walt to hide his gun right?</i>
</p>