IS300

iTrader: (2)

OKay heres the deal. When ever I take my car out of gear and come to a stop, my RPM jumps below 1k and jumps back to normal RPM level. This happens all the time and it is very noticle at night since I can see the lights dimming. It is as if the car wants to stall out all the time I come to a stop. FYI, my car has stalled out while driving!!! (going 40mph). What could be the problem? The battery? Alternator?



Mods:
Gutted uppipe
HKS downpipe
Samco IC hoses
Cat back exhaust
Unichip
Sound system
(i only listed the mods that might have effect on my problem)

Daredevil

iTrader: (5)

how big's your sound system? might need more power from your battery?

this is prolly horribly wrong, but its my only guess

IS300

iTrader: (2)

I have a headunit, 4 pioneer door speakers, and 1 12" sub in the trunk. But when i had it installed, my friend made sure and took the volt meter and measured it. He told me that it was at the right level and that i shouldnt have a problem. However, this sounds like the MOST reasonable explanation for my problem. Possibly the alternator went bad as well????

gogo_yubari

iTrader: (2)

from what was stated, it is most likely your alternator going bad. get a bench test for it. also, how often to do you drive your car at high rpm's? do you race your car with the sounds on? if so then it is most likely the alternator. you may want to purchase an upgraded alternator for your sound system, one that is able to power being drawn from the sounds. have you checked your battery too? it could just be the battery. do you have an optima/dry cell battery?