[glass.greg3]

I have a 4th gen firebird with the 3800 v6 and I get this code and I can't figure out why I changed throttle body still no change it happen once in a while my reduced engine power come on. Code are p1516 p1220 p1120

 

[Injuneer]

You can download a free copy of the 1999 factory service manual here;

MediaFire

MediaFire is a simple to use free service that lets you put all your photos, documents, music, and video in a single place so you can access them anywhere and share them everywhere.

www.mediafire.com

Codes are fully explained, with logic diagram for diagnosis. Does require a Tech 2 for complete analysis.