subwoofer caused car to go into limp mode??

hey,
so i just installed an aftermarket sub and amp into my sedan firing through the ski port. which is awesome and whatnot....but yesterday, was stuck in traffic on toorak road not moving at all (if you live in melbourne australia, you'll know what i mean) so i decided to check out just how loud i can pump my new sub.

so i'm sitting there idling, turning the volume righhhtttt up
cars shaking, people are staring, so i turn it back down
traffic starts moving, and i start moving, and almost stall (manual)...so i was thinking what the eff? but start creeping along with the traffic
then i realise the cars still shaking, cept the music is really soft
rev the engine a bit, and it's shaking heaps
struggles to get to 4k rpm, and is misfiring like an old V8
plus i'm getting a staccato beat, making it sound like a cylinder or 3 are out.
manage to limp it home, stopping the engine and starting makes no difference.
anyway
disconnected the battery, left it for a while, and when i got back it was as good as new
now the amp i put in isn't all that powerful (2x200W bridged, and my sub only takes 150RMS, so i haven't even pumped the amp all the way up), but could the voltage fluctuations from the amp have set my car into limp mode? i know the bmw electronics are more sensitive than most, but has this happened to anyone else?
hasn't happened since, and i've been pumping it up a fair bit. makes me think it might just have been coz i was idling (i.e alternator output was v low.) or maybe just bad luck/coincidence

anyway, i'm not worried enough to install a capacitor, coz i'm not gonna be pumping in that hard with the engine idling ever.

EDIT: Also, the strange thing was, nothing came up on the dash, no engine light, nothing.

cap won't help the idling thing, it's to protect the system from peak loads when your overall available voltage is there. It may not be enough when you are just idling.

You may have something else coming up, keep your eye out for SES lights, it not as you say just don't worry about it.

Originally Posted by franz

cap won't help the idling thing, it's to protect the system from peak loads when your overall available voltage is there. It may not be enough when you are just idling.

You may have something else coming up, keep your eye out for SES lights, it not as you say just don't worry about it.

Thats exactly what I was going to say.

k thanks
was just weirded out by the lack of any engine/SES light