I know this must be a "newbie-as-hell" question, but what is a J-spec engine and do these engines typically have a rough idle that can't be smoothed out? Also, how can I tell if my 1994 Mazda remanufactured engine is, in fact, a J-spec...?

 

a J-spec engine is an engine from a car (RX-7) straight from japan. most likely the idle can be smoothed out.

 

Thanks for the info...