battery voltage

[coach34]

I just had a new battery and alternator installed in my 1999 chevy tahoe. I'm still having problems with my battery voltage increasing when I apply the brakes with the headlights on. The problem seems not to occur during the day with just the running lights. Tahoe starts up very strong, battery indicator is normal when idling with the headlights on but once the brakes are applied voltage increases and Tahoe seems to want to stall. The Tahoe only has 63,000 miles. Anyone have any idea what the problem may be? Any information would be much appreciated.
Thanks

 

[kcb37]

Could be way off, but check for vacuum leaks.
Specifically the brake booster.

 

[bsamoul]

I did a big 3 upgrade to not worry about things like that.