This is totally an educated guess. That wire you disconnected most probably is to the MAS (Mass Air Sensor). There are probably numerous posts on this subject. Do a search on this site.

In essence , this device feeds a signal to the engine computer(s) based on air flow. I understand you can buy just the part that sticks out in the airstream versus buying the entire unit.

I also recall reading that there is a new product by CRC that is for spray cleaning the MAS sensor. The sensor thing is sensitive to dust in the airstream. Changing air filter according to maintenance schedule is a good idea to try and prevent this $200 part from wearing out.

Steve