You can replace the EACV for under $150 if you buy used.

The EACV (Electronic Air Contol Valve) is an important part. Don't drive with it disconnected, it may stall or do other funny things that you won't like. It is the main idle controling valve in the car, and adjusts itself depending on engine load and whatnot.

The car will also probably throw a code 14 when it is disconnected.