Engine light- Infiniti I30 help?

[MedeivelReign]

It's a 1996 Infiniti I30, when we connect it to the diagnostic instrument no codes come up- since we replaced a couple of sensors. But the engine light keeps coming back on,
preventing it from passing inspection. Any advice please!? How to get the check engine lamp to go off once and for all?
Nothing wrong with the car

 

[jenn0404]

My car did the same thing twice. Both times 87-octane gas had been put into the car. (by my teenager). It caused my engine light to come on. 7-10 days after refilling with 89 octane gas, the light went off for good. No repairs were necessary.