P0171 2011 Ford ranger

Question

Things were fine until my last oil change, and now I get the P0171 code (only P0171) which comes and goes. I tend to get it about once every 3 weeks, and it always seems to happen when I have just started the car and had to turn the wheel a lot, i.e. backing out of a tight parking space which requires me to go forward and backwards with tight turns. There doesn't appear to be any lack of power, but I do notice that my mileage has fallen over the past year from 27 mpg to 25.5 mpg average.

Answer 1

P0171 System too lean

Anytime the CK ENG LT comes on, you will exceed manufactuers specification. and you will consume more fuel to maintain fuel control. When the system is too lean the ECM will richen up the fuel system to control pollution. When you mention oil change is the level proper and not overfilled? With a  lean condition it is   more of a vacuum leak  during oil changes the air filter is check is the airfilter air duct properly secured and not causing any air leak past the air flow meter? That needs to be checked. One of the successful repair of dealing with P0171 is the cleaning of the MAF (mass air flow) Ford recomends brake cleaner as the solution cleaner.