[Svartalfiar]

I have heard that this story is a myth. I know that in the 1980s Pemex sold a grade of gasoline under the name “Nova”. If Mexicans understood it to mean “doesn’t go”, I doubt they would have used the name.

The Spanish verb "ir" translates into "to go", but it's a very irregular verb. So "va" is the root form for most of the conjugations - yo voy - I go; ello va - it goes; tu vas - you go; nosotros vamos - we go; and so on. But, for much slang, the pronoun can be dropped - Vamos! can be translated as "Let's go!", or such. And, adding in "no" is the same in English and Spanish, it's a negation. Therefore, "No va" can be roughly/slang translated as "No it go", or "It doesn't go".

[Flash Bazbeaux]

I’m aware of all of that, but your explanation is like saying that English speakers understand the word manslaughter to be the sound a guy makes when he hears a joke.