Hello everyone,

I have just fixed my car with Bank 1 misfiring (replaced fuel injectors, one was stuck open) & keyfob issue (fixed damaged chipset).

Car runs smooth and great but my LTFT is staying up high like 15%~18% with pretty low mpg, with intermittent P0174 (system too lean, Bank 2) code on and off. (no other codes, no misfires, runs fine on every rpm range, no CEL) (when I check with my OBD II reader, it shows P0174 as pending, sometimes its gone)

I saw some people say it could be the vacuum leak, some people say try resetting the learned system by unhooking battery for 10 mins since my previous misfires probably have taught computer to dump fuels like crazy.

In the mean time finding vacuum leak, I am trying to reset computers but I have read bunch of horrible threads about 2012 xf battery reset caused major issues and made the car into the brick.

Is this something that I should bring it to the dealership? Any tips or suggestion about hard resetting the system without messing it up?

Thank you very much!
Jin

 

Correct way to do reset for modern vehicle is by diag tool. Because ECU:s etc have nowdays non-volative memorys, the removing of battery might not do anything, exept harm. (that was the trick before non-volative memory price drop to the level acceptable to add on high volumes)

 

Thanks I have ordered PCV valve lids in case theres any leak. It was just $20 and some people had luck by replacing these for P0174 (system lean bank2)

if it doesnt work then probably upstream o2 sensor i guess. I cleaned and swapped L and R maf sensors but didnt make any difference so Im ruling it out. Am I in correct way? 😅

 

These are the way i would go. (Hint: smoke testers are quite cheap... )

You can try old injectors (working ones) as well, one by one, just in case some of new injector were faulty.