that is a long time sitting. A lot of things can happen in that amount of time. corrosion of fuel lines, fuel tank pick up, and rodents of many kinds, including spiders and their webs in places you could never imagine. Point is, I don't know what you have done to trace the complete fuel system is order to give you a good answer. Another area to trace is the electronics as corrosion in places again you can't imagine this happening. Like the fuse block. Make sure you clean every connection, every connection. To me, it sounds like blockage, or low voltage. Re-trace these areas and report back. I stored a '92 Camaro Heritage Pkg Z-28. I had the same problem of not starting. Come to find out, the setting rusted the catalytic convertors bad enough that pieces blocked the exhaust, causing the computer to shut the car down completely. Things happen when they sit for a long time.