It will shoot first nail but won't feed the next nail

Could be a few problems, the feed piston might be sluggish, the spring might be missing off the feed pawl, the collation of the nails or a bad coil of nails, the driver might not be retracting fully. Now for the way to check some of these. First look at the coil of nails and the adjustment on the magazine, the nails should pull freely off the coil. Next remove all the nails and using a block of wood "dry FIRE" the tool with the feed door open to check the movement of the feed piston, it should snap back and forth and if it doesn't that would probably be your problem, could be dirty/worn orings or debris in the air chamber. UNPLUG air hose and check for the finger spring that holds the feed pawl tight and check the pawls for wear and asphalt not allowing it to catch the nails. Lastly fire the tool and check the piston, did it retract fully allowing the next nail to advance? if not you would need to probably replace the o rings in this tool. Let me know if you need more assistance. And if I have helped you would you please vote accordingly, thanks