Hmmm,
To be honest I've looked at several pics of the MAC cold air kit, and have not yet seen the "plug-in" you are speaking of....
There are 2 versions:
One which is the MAF to fenderwell
The other is the throttle body to fenderwell, which includes a spot for your MAF
The above is a pic of the MAC TB to fenderwell system, I don't see any black plug in.
Could it be the MAF you are speaking of?
Do you have a pic so we can see what you are speaking of?
__________________
Uncle Sam
"What the hell is up with all the gauges?
Calling Captain Kirk, your ride awaits... Phasers on stun...."