2004 GMC Envoy • 6 cylinder 2WD Automatic • 101 miles

Had battery disconnected on 2004 Envoy, 4.2L. After reconnection, vehicle idled rough and nearly stalled when a/c kicked on. Forum stated that throttle body needed to relearn after being disconnected but could also be dirty. Cleaned throttle body and reassembled. Now even worse. Check engine light and reduced power light are now on. Everything worked fine before I disconnected battery so I don't think there is actually anything bad. What do I do?
July 16, 2011.

Check engine light on

Have the computer scanned for code/s-you have a problem within the engine management system that caused the CEL to turn on-This is your starting point of diagnosis,finding out what's going on.

Oct 14, 2011.