I just bought this car yesterday. I was driving it today and found that on a couple of occasions the idle would be very high. 3000rpm in park. I pulled the code and it indicates the idle control system high idle (code 507). Where do I begin??

Would it be the IAC? If so, do I clean it or replace it?

It also seems to shudder a bit under hard acceleration.

I am new to this forum. Any help would be great.