sounds like you are loosing fuel pressure...2014 Spark.
Idles great. Great acceleration. Will run all day steady at 5000 rpm. Once above 5000 rpm - symptoms of gas starvation. No misfire, just a slow deceleration of rpm once it gets to about 8000 rpm. Let off throttle and it either goes back to idle or dies. If it dies it is hard to start. Let it sit a couple of minutes and it starts right up.