I think my check engine light burned out?

[Walking Eagle]

In all seriousness, I thought once a check engine light came on, it stayed on until it was reset.

Two weeks ago, the check engine light on the F-150 came on, and the truck was running rough, felt like it was going to stall. This was the day after CORE, also the day after I accidentally put 85 octane in it, forgot I was not driving the Bronco. Anyways, I got the codes read, replaced the MAF sensor and air filter, hoping to take care of one of the codes. After this the light stayed off for a few days then came back on. Yesterday I filled the truck up with 87 like I normally do, and this morning the light was off and the truck is running smoother, still not as smooth as it should be, but better.

Will the wrong gas make it run lean? A couple of times I thought I was going to have to pull her over and shoot her.

[Hypoid]

The wrong Octane can make it detonate (Octane knock), which will cause the engine computer to reduce the spark timing, which will reduce performance, power and economy.

That is the grain of truth behind people getting better fuel mileage with high octane.

[Walking Eagle]

Even though I unintentionally put in 85, I was surprised to see such a difference in performance between 85 and 87.