Left key on for few days battery dead I jumped it off and runs very rough when give it gas gauges go out and backfires

You've jump started your battery, but not charged the battery. When you rev it, the ignition system is draining more power than the flat battery can give. You need to leave the battery on charge overnight to give it a good charge. If the battery doesn't recover following an overnight charge, it may have droped a cell, and will require replacement. But before you replace it, give it an overnight charge.

Hi Did you leave the jumper battery hooked up while it was running? It sounds like the dead battery may need to be replaced. Jump it again and leave the jumper battery hooked up and then see if it runs ok. If it does run good you will need to replace the battery. I hope this helps. Rod