Quote:
Originally Posted by 02Terra
Boodie... did you ever have this problem again or figure out why it happened?
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Yes; it's because the Xterra was designed before reformulated gasoline. The oxygen sensor is sensitive to gas with any additive (10% ethanol around here; 85% some places); too much, and it will trip the SES light.
The bad part is that when it sets the SES light, it also knocks the timing back 6º...Because it's programmed to detect low octane gas and retard the ignition when knock is imminent...
I was getting the SES light maybe 5 - 6 times a year with 87 octane [regular] gas. Now I fill up with 89 octane, and get maybe 1 - 2 SES events a year. Same amount of ethanol, but slightly higher grade of gas which seems to make a big difference. I use Sunoco, BTW.
YMMV