Charge system light comes on for 1-2minutes at stop light when idling. Charge system checked and says good. Doesn't always happen. Any ideas?

 

You say the system checks out "good". What are the readings that say it's good.
It's obvious that the computer is detecting some abnormal readings and thus triggering the light to come on. I would have it rechecked. Do the test to replicate when the light comes on. Ex. Check it with car warm and in gear.
Possibilities are a slipping belt or battery going bad. Have the battery load tested also.

 

Or idle too low.

 

Cant get test done with light on. It goes off before I can get off the road. Cold crank amps good, battery good alt good...

 

Obviously, not "all good". The only reason the light would come on is if there was something wrong with one of the components; alternator, battery, wires, idle.

Check the connection of the large red wire on the underhood fuse box for tightness and corrosion. And the connections on the alternator and battery.

 

Welcome to the site, are the Serpentine belt and tensioner, are they in good condition?

 

That's why I ask above what the readings were. Saying it's "good" mean nothing.

 

May not happen for several days, then could happen a couple days in a row, the nit for several days... if there was a bad component it would stay on! Only at idle,which is not low, and goes off within a minute or two!

 

Then it MUST be gremlins! Since there is no such thing as a loose wire or slipping belt.

 

How can that be ?