I have an 02 Z28 With a 600w amp HID lights and all the bolt ons and an SLP underdrive pulley. Is there anyway of fixing the low voltage without getting a new alternator? It only does it at idle and especially with rear defrost on.

 

Have you tried bumping the idle up a little, or doing the Big 3(upgrading the + and - cables)?

 

You could always stop underdriving the alternator.

 

Yeah, but it's a pain in the **s to get it right or it idles funny.

 

Just take in and have a tune done and have the idle speed bumped up, or if you have a programmer do it yourself.