Hello, this is my first time on here and I need some help, I just replaced my PCV Valve on my 1995 Lumina Sedan. The motor in the car is the 3100, and now I am having a problem. My car's idle is too high and my Service Engine light comes on while the car is in Park, but as soon as I shift it into gear out of Park the Service Engine light goes off. While the car is in gear it will idle over 20 MPH without me touching the Gas Pedal. If anybody has some insight into this problem it would be greatly appreciated.

Thank You in advance.

First off take a look for any unhooked or broken vacuum lines or connectors, if none are found take it to your local parts store most scan for codes for free.