@TDWTF123 said:
@LurkNoMore said:there are two adjectives and one noun so it is obvious which one is being modified (the noun)
Round objects. It is perfectly possible for one adjective to modify another. @LurkNoMore said:If, as someone else suggested, it was rewritten as "awful automobile metaphors"
That was me as well. And it's required, unless the intention is to imply that the metaphor was self-propelled.
Automotive (adj.)
1. relating to motor vehicles
2. self-propelling
The poster was using definition #1; you were using definition #2 and pretending it was the only definition. "Automotive" is perfectly acceptable here.
And no, a comma is not required, because the word "awful" is modifying the noun phrase "automotive metaphors." Hyphenating any two of those three words would be completely wrong in this instance.