Hi, I own a 2015 es auto Mirage. Bought it almost new at 5 k miles. until 46 k miles I always average above 37 mpg.
Now the best I can get is 27 mpg. I changed, oil every 5k with mobile one full Synthetic. New air filter, New brakes, " made sure they where not the the problem" use good quality gas, not the problem. Not hard on the car. nothing has changed since I owned it a long time, same style driving. When the issue started thought maybe spark plugs, changed them didn't change. change air filter didn't matter, checked tires brakes, gas no fuel leaks... asked Mitsubishi they have no clue, asked my uncle a retired master mechanic he has no clue. Seriously Im lost. Anyone have any deep insite. No engine lights shifts fine. I also check my mpg manual each fill up and it correlates to the cars readings, so that is not the problem. Any Ideas? seems to run great just mpg is horrible for this car!