A tip for the future, don't check to see if a fuse is blown, check for power to both sides of the fuses. It's quicker than removing the fuses to check them, and it shows if they have power to them as well. There are dual LED test lights that have a clamp for power an ground, then one color lights for hot and the other lights for ground. You can check every fuse and both sides of the circuit in about a minute. Hot both sides, fuse is good and has power; hot one side ground on the other, fuse is blown but the rest of the circuit is good; ground to both sides, fuse is good but doesn't have power. This is how I do it, so when you said the fuse was good, I assumed the wiring was good as well.
To test it further, run a fused jumper wire of the appropriate amperage to the "after" side of the fuse. All the fuses in that row of the box will get their power from the same side, so put it to the other side and see if it starts/runs. If it does, you can put the tank back up. You'll need a wiring diagram to see where the power for the fuel pump fuse comes from. Sometimes they go straight to B+ through a splice in the fuse box, other times they are one of several fuses that go through a larger fuse. That means that if you have checked every single fuse everywhere else on the car and the only fuse with no power to it is the fuel pump fuse, there is a problem in the wiring. Common places GM hides fuses from you include: Under the hood (can have multiple), both sides of the dash where the door closes against, under the dash, in the center console, under the rear seat, in the trunk. I havn't had to find them on a Cobalt yet, so check all those places for extra fuses, and don't look at it logically either (you need to think like an engineer). A wire can go from the battery and then through 3 fuse panels in different parts of the car before it goes to the device. You're getting very close to finding the problem, and it will probably be a cheap repair too.