Big stereo and shifting problem!? HELP!

[D_Car777]

I have 03 5 speed auto. I just put in a monster system.... 2 fosgate t212d4 (2000 watts) and 2 fosgate db1000 (1000 watt amps) I'm running only one battery and 4 gauge wire. When I have the stereo up all the way (where my vision is blurry and my rear view shakes out of place and the car almost stalls at red lights) When I start to drive, the car hesitates when shifting and shifts HARD. What the hell? Any clue? Thanks guys.

[audtatious]

The audio system is putting an extensive load on the charging system. Due to the load, the engine is probably having problems getting a strong enough spark.

That would be my guess.

[smockers83]

Your system is putting a huge load on your electrical system and with an automatic, shifting is done by electronics. Invest in a capacitor and a better battery. You may even want to invest in a better alternator with a higher amperage.

[joe603]

I have the same problem with my MTX stuff. It was worse when I didn't have a CAP and a yellow-top Optima battery. That would be the first thing I recommend.

If it still does it, an upgraded alternator will be needed. I've heard that the Nissan Quest has an alternator that will fit in the G, but I haven't tried it yet. You're kind-of in uncharted waters...Nobody seems to make aftermarket alternators for the G35.

Smockers83 is right, the AUTO trans is being affected too. Because you have an AUTO, I'd also recommend a grounding kit.

Good luck! Let us know if and when you find a solution!!

[Gimli G35]

very big load on the car , as what joe said New battery made for big loads

and our alternators suck to be honest .. and also dont get Unorthodox racing underdrive pullies