[1fastsedan]

i put a 91 5.0 in my boat and i am having issues with the idle. i pulled codes and here is what came up 31,67,81,82,84,85. i am not running smog so i know 31,84,85 are for that reason. but will this effect the way the engine runs? is my IAC bad, i purchased brand new. how about 67 nuetral safety, will this effect idle? how far does the air filter have to be from the maf sensor? thanks