97 Sentra, Check Engine Light: P0440, P0446
Check Engine Light goes on shortly everytime after I add #87 gas. It went off after I added #91 last time, but came back again after #89 gas this time.
Checked the codes: P0440(Evaporative Emission Control System Malfunction) and P0446(Evaporative Emission Control System Vent Control Circuit Malfunction).
What can I do to this probelm? Have to use Premium gas all the time? or there is some problem with this car?
It's a 1997 Nissan Sentra GXE, 82K miles.