high idle and missing on 2004 Jeep Grand Cherokee

Rookie cbe0621eac06868b3efe0d8d1d3611e23c60d3114864ea2ec19a68cfbd3eebab
my jeep will rev high to 2rpm when first starting it up. i turn it off and restart and it acts normal. it has been known a few times to rev high while in park. so i shut it off and back on and it does fine. also when driving the rpms will fluncutate up and down and the engine feels like its missing. i have replaced the idle sensor. it still does it. the check engine light doesnt come on. im at wits end! please help.
(1) Answer
Try diagnosing the problem with a scantool you may have a pending code, i would also check to see if you have any lines broken from the air inlet