High Long Term Fuel Trim
I drive a 2014 Ford Fusion Titanium (2.0L turbo). In the past 3 months, I have had the evap hose assembly (including the purge valve) changed. The upstream o2 sensor was changed and is reading normally. The air intake manifold was thoroughly cleaned via walnut blasting. The engine has been smoke tested several times with no vacuum leak found. I’m still seeing high LTFT readings generally around 21%, while the short term fuel trim stays in the low single digits. The LTFT readings drop to about 10% when accelerating. The fuel pressure seems normal as far as I can tell, hovering about 250 psi at idle and reaching into the 2000s while accelerating.
What could still be the culprit for these high readings? The engine runs a little rough at idle but nothing crazy or super noticeable.
I forgot as well all of the spark plugs were replaced and the several fuel pumps were replaced when I got the car back in 2021. It’s at about 160k miles.