In my '98 Bonneville, when I brake to a stop, my battery voltage dips pretty severely, sometimes into the lower critical region. It happens most often when I’m stopped at a stoplight or stop sign, and if the blinker is on the blinker rate will slow as the charge goes down. Sometimes I can watch the charge drop as I sit there, and I wonder if the car will shut off before I go again. As soon as I hit the gas the charge goes back up into the normal range. This only happens in drive; idling in park is not a problem. This isn’t normal, right? Is this an alternator problem? Maybe a sign that it’s about to need to be replaced? Don’t know if it’s related, but every once in awhile (1 in 10 starts)the car hesitates when starting. It’s like the starter motor begins, then pauses completely, then starts again and the car starts fine and runs ok after that. Maybe a related issue? I don’t know. Someone please advise. Thanks.
Check the alternator belt tension and make sure the battery connections are clean and snug. If that doesn’t help the battery may be going out or the alternator output may be low. Have a load test done on the charging system to see what shows up with that.
A battery may be in your future. As Couger suggested, get it checked and keep Murphy out of your life.
Go to any auto parts chain store where they will load test your battery and charging system.