hey im new here so sorry if i do something wrong...but i have a 1994 z28 camaro with a rebuilt lt1 basic mods... exaughst intake ...it has 411 gears in it as well...but lately its been idiling high also at about 3000rpms it will missfire i was wondering if anyone had any idea whats wrong?

 

You could start by checking that the throttle blades are fully closed at idle (check linkage & cables for binding), and that all vacuum hoses are in good condition and not leaking.