Last night when I turned on my HIDs I noticed they light up with different colors changing rapidly.

Blinked on white, turned blue, suddenly reddish orange, then finally light purple. (They Flickered alil while Doing So)

Never noticed this before.

Is bulb on the way out ? Or is this normal?

Oh yeah 8600K Zmax Kit

 

The bulb is on it's way out.

Your 8600K will turn redish and will get noticably dimmer.
Flickering is a sign of the gases being spent...

2 questions,

how long have you had these?

Manuf. of the bulbs?

 

gases being spent in that it's having a hard time Igniting...

 

z-max=hanabi=pure crap.

Your bulb is going to hell. If you want replacements, go to globalpremier.com