Am having a very difficult time with a p0171 on a 2013 fusion 1.6l. Ford dealer diagnosed as needing injectors and a intake manifold gasket. Has since had injectors, high pressure pump, hi and low fuel pressure sensors, upstream 02 sensor, Evap purge valve and line assy., intake gasket, and oil separator gasket. PCV hose and vvt solenoids per ford tsb for a p0016. Long term fuel trim at idle is 25%.
Any issues with coolant or overheating?
https://media.ford.com/content/fordmedia/fna/us/en/news/2017/03/29/ford-issues-three-safety-recalls-and-one-safety-compliance-recal.html
No issues overheating or coolant loss. I do know of the safety recall. Noticed signs of fire damage on plastic pieces here and there. Am unsure of the vehicle history. It also has heat tabs on motor. So may have been replaced. Car has less than 60k on it. Have smoke tested several times tightened all charge pipe clamps. Low side fuel pressure is at 70psi at idle. High fuel pressure Is close to desired at all times. Have even replaced valve cover as I removed it to check the plastic check valve. That I guess is their version of a PCV valve. Car runs good fuel trims come down when driving. Even passed emissions obd2 test, but if you let idle long enough and cycle key. Will throw p0171 code as the long term fuel trim will max out at 25%.
Have you checked the sensor condition : IAT, IAT2, MAP, O2? At least the first 3 you can clean with maf sensor cleaner.
Fuel is used not only to power the engine, but cool it as well. Not sure this applies here, but during extended idle, if the fans do not kick in, raising fuel trims would be one way of controlling runaway temps.
It also may be something that needs a programming update to fix.
Wiil dig further.
Have checked and cleaned MAP sensor and Intake air temp sensor by air filter. MAP reads 29hg engine off and around 10 at idle. New upstream 02 sensor didn't make a difference. Had found a exhaust bolt backed out by where the down pipe connects. In front of that 02 sensor. Tightened all the bolts and installed new 02 sensor. Thought for sure that was it. Never sounded like a exhaust leak but I know a leak in front of sensor can throw off readings. Have not checked IAT2 guessing it's on or near intercooler. It takes a bit to throw code but fuel trim rises quick and suddenly after a minute if that. Even from a complete cold start. Will start at 15% cold and then go to 25%
Ok let me get back 2 you, may be some common issues i have not run across yet.
While this applies to a 2.0EB per Ford, might be worth a check
TSB 13-1-4 2.0L GTDI – ROLLING/FAST IDLE – DIAGNOSTIC TROUBLE CODES (DTCS) P0507, P0171 AND/OR P0174 – BUILT ON OR BEFORE 9/28/2012