I've had my SES light on for months non-stop. It has been scanned and a misfire was found and turns out I need a new opti, rotor, and plugs/wires. Also need a new heater hose as well.

So anyway, I've been having some extra cash on hand lately so I decide to fill up the tank completely with Chevron (93 octane of course ;p).

After that tank was out, I fully replenished it again with Chevron. After about a dozen or two miles, I started up again one day and the SES was off. It has been this way for about 2 days staight now.

What would exactly cause this? The symptoms of needing a full engine tune up and opti hasn't gone away yet though of course. Just the SES light is off.