Ive got a problem with the idle. Its not making the act funny but it worries me a little. Sometimes it'll drop from 900 down to like 100. It wont turn off but i feel the car rumble as if it was. Any ideas on what is causing this and how i can fix this?

 

Does this occur when you come to a rolling stop or just w/the car idling in neutral?

 

maybe acv?

 

When i go to a rolling stop

 

It's rather normal.