My check engine light came on a few weeks ago. Well while my dad and I were doing some diagnostics on it to figure it out, he was under the hood and he was messing with this idle screw, as seen in the picture. I didn't know he had planned to mess with it.

So my question is, did he mess with the engine management at all? The car seems to be running properly. I figured whatever he did there the computer would compensate for it. I just wanted to double check with somebody who might know. Thanks! 96 2.0 GS 5 Speed