I am getting Check Engine Light, I used my scan tool and got his Error Code:
1- P0171 -- FUEL TRIM TOO LEAN (BANK 1)
2- P0174 -- FUEL TRIM TOO LEAN (BANK 2)
What happened I was driving and need to refill car with fuel, I used to fill it with Octane 95 Fuel, but at that time I were not able to find it so I fill it with Octane 91, after driving for two days this light appears and I got this Error code.
Could please advise if this is a serious problem or not.
Injection cleaning on 2008 Mercury Mountaineer