The car: 2004 G35 Sedan with zero mods

Stereo consists of Pioneer head unit, JL Audio 300/4 and a 10w6 with 4 gauge wiring.

When I'm listening to the stereo at high volume, the transmission "studders" when the bass hits. I'm assuming that I may have a loose ground somewhere with the TCU or ECU. So my questions are as follows:

1. Where do I check for these possible bad grounds?
2. Should I consider a CAP (even though I'm not running any high power amps)?
3. My lights don't dim or anything so it can't be that much of a drain, with that in mind....

Any other ideas/advice on how to fix this problem? The studder/shudder is VERY pronounced, like the tranny is GOING OUT when this occurs. Turn the radio down and the car drives like a champ.

 

Grounding kit would be worth a shot.

 

Since you amp will be the main thing that'll be messing with your current, I would opt for a 2G ground. Is the ground running to the battery or to the frame? I always run my grounds to the frame if possible.

Check the condition of your battery. If you're still running the stock battery, drop it and replace it with something new. My OEM battery took a dump at 55,000 miles and they are notorious for not lasting very long. You can go the route of getting an Optima battery, but that might be WAY overkill for your amp.

Adding a cap really won't make a difference if your grounds aren't optimized. Like NFSP said, a grounding kit will help, too.

Your lights will not dim noticeably if you have HIDs because they require much less current to stay lit; however, they need more current to kick off the arc but that's only when you turn them on.

I'd do these things in this order and only advance to the next step if the problem persists:

1.) Replace battery if it's dying.
2.) Run amp ground to frame with heavier gauge wire (make sure you strip the paint at the contact)
3.) Run a grounding kit.

 

Thanks guys. I'll try this over the weekend and see if that works.

 

Caps are worthless unless you're trying to score visual points.

Grounding kit helps shifts in the auto generally, but I think it's the battery itself that might be going.

Or where your 4 gauge connects to the batter has pulled it a little bit loose so the battery can't supply that needed power when things get tough.