High rev electrical issue

[BDSCRPN]

Okay I've searched and searched this one out but no answers yet.

Car:
2000 v6 3.8L
5 speed
optima red top battery
GT MAF with GT cold air tube
Factory stereo with after market add on rca amplified with 600w jensen 4 channel bridged to 2 with 2 12" subs 1.5 micro farad cap (this may not be important but just in case)
Also I've owned the car since was still under factory warranty, one prior owner no mods done till I got it. Even then nothing major.

Problem:
Under load and in the higher rev range 4k plus, battery light shows. Then radio and instrument cluster blank out. Meaning completely dead for about 2-3 seconds. Then at some point the cluster comes to life all dials read make then drop dead and come back to life where they should be. battery light remains for about 10-15 seconds and engine is still running during this entire time. never misses or loses power at all. First time this happened it would only happen even with car stopped in parking lot at 4k +. Granted with car stopped and out of gear maxes at 4k then limiter kicks in anyway. but even in neutral rev to 4k and bat light comes on stays on for about 2-3 seconds then goes off. Newest electrical item in the car is the cap. I did install correctly been working with electronics and electrical all my life. Did pull the amp fuse under hood and didn't seem to have same issue at 4k. However has been disconnected for a while now and problem keeps rearing its head every so often. Amp and cap have remained disconnected so not the problem. Thought maybe cap was causing the issue cause never had any electrical issues before. Cap was installed for about 2 months never had any issues at all. I know lot of info but figured might help.

Anyway any suggestions or ideas would be appreciated. I'm to the point I don't care how wild as long as they are realistic.