I've had a hard starting problem for a few days. It was setting a code 54. Did the search thing in the archives and got some god hints. Most seemed to say to check the fuel pump relay.
So I checked the voltage at the connector back by the fuel door. It was showing 12 volts. This seemed to rule out the relay, and I'm fairly certain the fuel pump is OK because I changed it out just a few months ago. (By the way, this is a really easy job - about 30 minutes. I had a '85 TA LB9 that I had to change the pump also - took over four hours to drop the exhaust and rear end to get that fuel tank down to get at the inspection door. Gotta love those Vettes :) )
Some other posts in the archives suggested cleaning the contacts for the fuel pump connections, inside the tank. So I opened it up again. There was quite a bit of surface rust on the under side of the inspection door, so I cleaned it up the best I could and cleaned all the electrical contacts with 320 grit sandpaper and spray contact cleaner. The flange for the plate was pretty grungy too, so I wire brushed that, only to notice that it was warped around some of the bolt holes - kind of like the way oil pans warp. So I took my Ford wrench (16 oz. ball peen hammer :D ) and straightened 'em up!
Had to order a new gasket from Chevy, so I went ahead and ordered the relay while I was at it. Not sure if the relay was bad, but I couldn't get it to work by applying 12V to it (disconnected).
Anyway, I got the parts today. Installed the relay (new connector also - it looked really bad!), and started her up. No code 54! :D :D
I suspect that cleaning the contacts did more than anything else. I was getting 12V at the pump before (yes, with the engine off - I learned about the oil pressure switch from the archive stuff also). But who knows? Relays are weird animals.
She's running and I'm happy!
Thanks for all the help!