2011 Ford Ranger 4x4
 

Does anybody know if a 2011 Ranger can use high octane gas? I tried 2 tanks and my milage has gone out of sight. I read my book after putting the gas in and it said that my engine will not run on it. Engine is a 4L. How can i get my milage back. Any ideas?

What kind of mileage are you talking about? What was it before and what is it now? Using higher octane fuel in an engine designed to use a lower octane fuel normally gets less MPG as the higher octane fuel is harder to ignite, thus the flame front starts later than it should and any power generated from the ignition explosion occurs at or after TDC instead of before TDC like it should thus reducing power and MPG.