This morning I noticed that, while in gear, my car was idling around 500rpms. However, if it is Neutral, the rpms rise to normal levels (around 800). This has never happened before. It doesn't surge or stumble, it just idles at 500 like that's where it is supposed to be. Last night I uncapped the cutout, but it seemed to be running fine then. Any thoughts?

98 Firebird Formula, A4.
Modifications: cutout, MAF ends, K&N.

 

800 is a high idle speed for an A4. they are programmed to idle at 550 - 650 rpm.

It may just need time to adjust to the uncapped cut-out.

 

The problem is that at this low a speed, the converter isn't hooked up (I think), and I actually have to give it gas just took hook up and get it moving. It's very disconcerting.