Premium gas makes it work better!?

[VanillaXT]

On a whim, I decided to put in a tank of 93 octane premium gas (BP branded station that just recently changed from Shell) in my 2015 Xterra. I couldn't believe the difference. On the regular gas at the same station (87 octane), it worked "fine" but it had a big lag in acceleration at a certain point. Once I was at a steady speed with the regular gas, I needed to add a LOT of throttle to get it to move off of that speed. Since I'm new to the Xterra, I thought that was just the way the engine was set up. Surprise! The premium fuel has mostly gotten rid of the issue. But WHY?

It's winter here in Minnesota, so did the regular gas have a poor additive package, more ethanol, or more water contamination? Does my engine with only 55k miles actually need premium fuel. The car was not driven very much before I bought it, and may have sat for long stretches. Could the engine have had deposits in the fuel injectors, valves or intakes that were removed be the premium additives in the 93 octane?

Has anyone else tried premium gas? If so, what was your experience?

 

[Muadeeb]

Do they like premium, well maybe. I ran my Gen 1 with it for about a year, tracking mileage and m/$ and it was about a wash. Do what you will.

 

[meisanerd]

How much ethanol are they dumping in the gas? I've tested a couple different stations with the same octane, but different amounts of ethanol in it, and less of that made more of a difference than switching octane.

I personally run the 87 from a decent station, going above that I dont notice enough of a performance difference, and the mileage gain to price difference usually comes out either the same, or worse than just using lower octane gas.