I looked at a 1989 sc recently that had not been started for several weeks and temperature outside was -10 F. It emitted a black soot out tail pipes and ran very rough. Once warmed up it was fine and exhaust was normal. The only code that came up was 21. Can anyone tell me if this is a warning sign of trouble down the road, or is the extreme cold the cause. Car has 120000 miles and head gaskets replaced a year ago.
Thanks,
draft
Thanks,
draft