I was pulling put of the drive thru the other night. I sat waiting to turn then I turn my heat on defrost and floor. Suddenly the voltage drops and engine starts to run roughly. When I turned it off it returned to normal. So I did it again and then it started the same problem. I left it on and fluctuated the speed of the blower then it eventually leveled out. Any ideas?

2003 Bonneville se

I did have a code come up a week ago for the catalytic converter and wheel speed sensor
But that's about it.

welcome to the club Pickles!!

I would first check the battery and alternator output. that happened to one of my W bodies that had a rewound alternator: the headlights would also

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poverty forces one to do unorthodox things

2000 SSEi
past rides:
1996 SSEi
1992 GTP
1987 Grand Am

Sounds like a weak alternator. I'd have the car tested at your nearest auto parts store, it's typically free.

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-Car Guy Carl
"Penelope" - 2003 SLE - 247k Miles
"Sydney" - 2000 Honda S2000 - 98k miles

I did just recently replace the battery. Thanks for the advice I will be checking the alternator asap. I can just do that myself right? Just check the charging output?

And thanks for the welcoming.

If you have a multimeter, you can test charging system output AND , also very important check for failing diodes that are adding AC into your car's DC electrical system
http://content.amprobe.com/appnotes/AMP ... ppnote.pdf

Too much AC is bad because it messes with the way all your car's electronics , such as the computer, work.
It can burn out ignition control modules and other significant electrical items.