Toyota: Nissan Fuel Sensor, dashboard lights, nissan frontier

Question
I have a 2005 Nissan Frontier, 2WD, 4cylinder truck, about 80K miles. I've done all recommended maintainence on the truck and do not use it to tow.

A few months ago, I got gas at a station I'd never been to.  Immediately upon starting the truck after fueling, the check engine light came on, the low fuel indicator was lit and the gas gauge showed no movement (as if the engine was not turned on).  Prior to fueling, the tank registered at just over 1/4 full with no dashboard lights.

I drove it home and took it the next morning to the shop that does all of my maintainance.  They diagnosed it as a faulty fuel sensor and recommended I replace the fuel pump.  

It seemed a big expense for the truck at the time, so I decided to wait.  I keep track of mileage and know how much I get on a tank of gas, so thought I could live with it for awhile.

The next day (after perhaps 2 hours of driving), the low fuel light went out and the gas guage registered full.  Over the following week, the guage was accurate. The 'service engine soon' light stayed on.

As the tank got down to about 1/8th of a tank, the service engine light went out.  Shortly after that, the low gas light came on.  

I got gas at the normal station, and the same thing happened.  Service engine light on, low fuel gauge on, and no movement on the fuel guage.

Over the next few hours of driving, it corrected itself again.  

This pattern continued for 3 more fuelings.

Then, last week when I fueled, the lights all stayed off, and the guage continued working.  

Is it possible that the fuel sensor was affected by 'bad fuel' and has now been dilluted to the point its not an issue?  

How can I avoid this?  My dealership says its not covered under the warranty left on my vehicle, but the mechanic admitted to me that the sensor may be defective, but has not been recalled.

Answer
The question is: What KIND of fuel did you buy?

If you bought "E-85", that 85% ethanol crap, you can expect huge fuel-related problems. The ethanol attacks the fuel system components, as Nissans are not "E-85 friendly"...E-85 is BAD NEWS for Nissans.