So, I have a 2016 ford mustang EcoBoost that recently had a p0442 code. Took it to the dealer and they told me it was the fuel filler neck (the door inside had become bent so I was able to limp it for a bit by putting duct tape over the fuel port). I ordered the part online (OEM) and had the part installed by another shop (good reviews and seemed professional enough on inspection) because dealer was too much. Got it back and the thing drove perfectly. I also checked and I saw that the permanent code has disappeared, so we were good. Welp about a few days later the CEL appeared, and it is the same code. On a whim, I reset the code and performed a drive cycle. I checked afterward and it said all of my I/M systems were good including my evap. Well now the CEL is back on, and I am at a loss.
Does anyone have any ideas on what could be causing this code so strangely?
I mean a small EVAP leak on a ford is typically the cap less filler neck. They supply a special funnel to clean these out. Could very well be the purge valve.
As a side note if you take it to a reputable shop and ask for a diagnosis and not a parts change, we typically run service bay tests and can monitor the vacuum, how much it pulls, how it holds, etc, to verify the repair/problem. If you come in with a part and say replace this, that’s all I ever do. I don’t verify anything. Just install the customer part. (And it’s not to be a jerk, we just don’t flag if we don’t diagnose so there’s no reason to take the extra steps and verify or diagnose. Just slap a part and clear a code.)