I'm sure this could many of things, but not really sure where to start. I would say the car has always run a bit rich, and today, it seemed maybe richer than normal. It has never had a problem with an idle in my three years and always been pretty smooth.
I guess my question is, could the fuel pressure regulator cause this? Is there a more typical part that would fail causing this. It seems like it could be a vacuum problem, but I really don't know much about it.
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Thanks,
Zach