Home › Forums › Stay Dirty Lounge › Service and Repair Questions Answered Here › Nissan Sentra 08 (B16) Running Rich › Nissan Sentra 08 (B16) Running Rich January 6, 2020 at 3:22 pm #895680 HarryParticipant Replaced the spark plug Car still running rich, matter of fact nothing changed. Am thinking might be exhaust leak? But am confused, vacuum leak should cause positive fuel trim but this one is rather negative trim.