My Reduced Power light comes on while sitting at idle. When It goes above 3500 RPM the light turns off and it drives just fine. it comes back on while sitting.What could be the cause of this issue?

SOURCE: 04 chevy tahoe

the check engine light you are getting sounds like and electrical problem, have the battery and the alternator tested, and have autozone or the like pull the codes off for you and see if you can figure out what they are....

SOURCE: 2001 rodeo reduced power

I just went through this with my 2001 rodeo and the dealer needed to replace several parts over several weeks because they could not get the problem to go away.

-APP/throttle pos. sensor needs calibration/replacement
-air idle control needs replacing
-throttle body needs replacement
After months of going back and forth to the deal with the same problem, the throttle body was replaced last week and the problem has dissapeared....for now...

SOURCE: 03 saturn L300, reduced power engine light came on

You are not the only one. Ive met a good many of Saturn owners (most were 2001 L300 drivers) but they were plagued with the problem you have and practically identical codes. The following remedies have been known to work:

1. Replacement Battery Cable
2.Replacement ECU Wiring Harness
3. Replacement of ECU

SOURCE: engine power has been reduced

I had the same problem. Took it to a Chevy dealer to be checked out. It turned out to be a wire that was loose that was connected to the throttle position sensor. They had just had three other 06 Impala's come in for the same problem.

SOURCE: service engine soon and reduced engine power

disconnect batt. for 30 min. then reconnect,if no problem exist the lights will go away