In the last couple of days my wifes Tahoe has had a problem starting. First time it happened she was driving it, dropped the kid of at the day care went out 5 minutes laer and I had gotten the call that it wouldn't start. She claimed it would just keep turning over like it wasn't getting gas. When I got there it started right up.

Next time it happened to me. Right away I noticed I could not hear the usual noise of the fuel pump as soon as I turned the key. After trying it several times throught out the day I had no luck. Now 16 hours later it decided to start.

Is this most likely the fuel pump that is going bad or could it be something else? I have had other vehicles where the fuel pump had gone bad and stopped working but not like this. At least not where it stops and then starts working again. Is there any way the fuel pump can be tested to verify that it is going out? Do I just have to take it to the mechanic and assume that I need to have the fuel pump replaced?

I have started the vehicle several times in an hour and have not had any problems. Don't really want to take the vehicle out of town if I can't trust that it is going to start.

Any advice on this would be greatly appreciated.

If it working theres not a whole lot to check. When it was not working was the time to see if the pump had failed. You'll need a fuel pressure gage (a minimum of 56 psi is necessary for the vehicle to start, one pound less and it will not fire up) and a volt meter. If your dig the wires out of the wire loom as close to the tank as possible you will see two grey wires. One of them supplies voltage to the fuel pump. Make sure one of them has 12 volts for a couple of seconds when you turn the key on and 12 volts anytime the vehicle is cranking. If the power is there that likely the pump has failed.

Make sure you check the harness connector that plugs into the module assembly. There is a known issue if the contacts burning up from excessive amperage draw. you see a brownish discoloration if this is the case.

Its not uncommon for pumps to start up again after failing. It just means they are on the way out. The symptoms you describe sound like it could be the connector, like Airjer said, but depending on the vehicle mileage if you have to pull the tank, you may as well put in a pump and be done with it.

Heres an article I did a while back. There are pics of the connector that gets burn up as well.
What happens when a fuel pump fails?