“what color is it?”

My first instinct on how to ask that question was “chay' nguv?” However, after I asked it that way, I immediately thought to myself that maybe that is asking about the means by which the car is colored (e.g. laSvarghDaq lunguvmoHpu' nguvmoHmeH qoqmey”) rather than its current state of coloration.

It can't mean that; you'd have to ask chay' nguvmoHlu'pu' how has one tinted it? to get that.

So I reasked as “Doq'a'? SuD'a'? chIS'a'? qIj'a'?”

That's really awful.

Your first instinct was correct. KGT tells us:

There is, however, a verb, nguv, which means something like “be dyed, stained, tinted,” though it is seldom used except in the phrase chay’ nguv (“How is [it] tinted?”) or when suffixed with -moH (“cause”) in the form nguvmoH (“dye, tint, stain”; that is, “cause to be dyed,” etc.)...

-- 
SuStel
http://trimboli.name