I have a 1999 SL I've been battling with for a couple years now. Here are the symptoms:

1. Sometimes will crank but not start. When I turn key on, I cannot hear fuel pump relay click or fuel pump run for 2 seconds.
2. Sometimes driving or just idling it will cut out, fuel pump shutting off. When it does this, sometimes it will just kick back on and run fine.
3. Every time it does this, the fuel gauge stays at 0 and the 'Low Fuel' light does not come on. With key in 'Run' position at times it will click on and off randomly. There are times I can just let it sit for a few minutes and it works fine, and others it has to sit for hours.
4. It does this in cold, cool, normal, warm, and hot weather, as well as when the car has cold start or been running.

I've checked and replaced fuses, relay, and wiggled wires to no avail.

I've searched and searched forums and either find topics unrelated, or when I do find one that sounds similar, I never see anyone post their solution to the problem.

Any more details needed I'll be glad to answer.

 

have you ever dropped the fuel tank?

 

have not. I have checked with test light at the relay and its not getting powered for some reason when its acting up, so I'm not thinking its the fuel pump itself or wiring back to it.

 

There is a couple of things going on here that may or may not be part of the problem. It seems you have pretty much guessed there is not power back at the pump. At least when the problem takes place. Also there is a problem that takes place with the gauge which seems to be related or maybe be related.
The problems with something like his is todays automobiles depend heavily on Electronics to function. And with out proper study of wiring diagrams and some basic electronic trouble shooting to verify anything at all, it is nothing but a W.A.G. as to what is going on.
My first question would be is the power being turned off as a function of some other problem, or is the power disappearing because of a wiring problem.
Knowing what codes the computer is kicking out at the time of the problem would help. As would being able to see the wiring of the car which like a road map, directs one around the wiring so it can be traced.
Knowing the codes requires a scan tool to read them or following the instructions in the service book you purchased from the auto parts store to allow you to pull them up with out a scan tool. You did purchase a service book didn't you?
Because you also need it for the wiring diagrams.

 

I actually have all the factory shop manuals for the 98-99 model years. Ill go dig them out in abit and find those diagrams. as a matter of fact, i think ive put one on here recently

 

Factory Shop manuals are certainly nice to have. The last one I purchased was for my '87 Fiero. A car that was different enough in so many ways that having one was a serious step in the direction of knowing how to wrench on it. Since then I guess I have been fortunate enough to have a Chiltons or it's equivalent.