Started up the GTX after it has been sitting since last Nov. Before I started I charged the battery, then poured some gas in the carb. the car started right up and smoothed out after about 1 mn. so I get out and am watching the motor run and after about 5 mn it just kills, like a ghost turned it off, its never done that before, I tried starting it and it fired right back up, I let it run for about 30 mn, then shut it off and started it a few times and it was fine.

Any idea why it would kill like that ? car is stock. tank was full and treated with Stable. could something be failing or ?