I dropped the straps on my '96 and the tank isn't moving. It doesn't look like it's caught on anything, is there a step I'm missing here or something?

 

You have to massage it out...the filler neck sometimes gets stuck. Oh speaking of which, make sure you took the gas cap off

 

GM added some rubber strips to eliminate rattling;chances are the rubber is sticking to the top of the tank. Don't forget your have 4 lines to disconnect also (gas out, gas in, pressure relief line and charcoal canister line) and an electrical harness.