I'm currently working on a friends 1994 4.6 marquis....I'm coming up with DTC code 412 (cannot control RPM during KOER high RPM check). so far i've cleaned the MAF sensor and IAC, I also checked the voltage supplied to both and resistance which looked good.....if anyone has had this problem or has any idea of where to look next it would be muchly appreciated

 

i've replaced the IAC and still have the same DTC code