the pump module disassembles and the motor is less than $100, not that hard to install once you have the module out (which is a PITA to remove, teh ring that holds it in is usually rusted shut abd breaks when you try to get it off) but anyway, if you let the tank run toward empty there is not quite enough gas in the tank to keep the pump cool and over time it will act up. Run intermittently and what not.
There also over time have been problems with the connector on top of the tank - I think the dealer would have an old bulletin about it. It happens rately so it is not a recall or anything like that, just advice to the service people about what to do if they see a prolbem like yours. A replacement connector that u can splice in should be available from a GM dealer. To check if this is the case, remove the plate in the trunk that's over the fuel pump (later rivs have it yours may not), clean the leaves and crap off the top, and use a meter to check for full or partial shorts.
Alternatively, someone with a Tech II can command the pump on and check some stuf form the drivers seat. Need a mechanic with real troubleshooting experience with a tech II for this.
Good luck
