UPDATE.
IT's BACK. well after about 50o miles since I reset the code it came back today. reset it and it went away but still logging a soft code for P144c. I guess I wil lbe digging deep for the leak the next few days. Will post if I find anything. I do not have a smoke machine so I plan on using my hand vacum and checking all the lines to see if I can find a leak.
Larry

 

Dang I hope I didn’t jinx you! Probably gonna do a smoke test on mine too. The part you sent me actually ended up being the same part I replaced at first. One of the main things I’m wondering is: What does the right hose on the bottom part of the part you sent me connect to on your truck? I see that the 2015 and 2016 F150s have a similar setup. I have a brass fitting screwed into my turbo inlet tube. I can’t figure out where the hose connected to that fitting was originally supposed to go. If you know where it’s supposed to go, it could end up being a common problem or leaky spot that some previous owner tried to fix on my truck.

 

Are you using Ford OEM parts? Does Napa sell OEM Motorcraft parts?

 

Motorcraft part no. I do not believe I am getting defective part from Nappa. exspecially 2 in a row. Yes the brass fitting is weird, looks like an aftermarket thing. I believe I have a leak. more to follow in a few days when I have time to check. thanks All

 

Another update
my CEL light came on as stated above but I was below 1/2 tank when it did. I have a 36 gallon tank, I reset the code twice and it came right back on. I filled the tank, reset the code and have put over 50 miles on with many start and start cycles and no code. strange it seems like the CEL comes on when tank is below 1/2. we rarely ever wait until its below 1/2. will dig deeper into it this wekend.
justy read where the PCM will test the system when the the fuel is between 25 and 75% full. this is just 1 condition it uses.

 

Code P144C Discription:
EVAP system performance test;
1. Test done during min Boost conditions.
2. Once every drive cycle when conditions are present.
3. DTC sets when fuel tank pressure exceeds a calibrated amount--->within a specified amount of time, during the test.
.
When you open the tank, internal pressure will go to Zero.
When you fill the tank or it's very low, the tank volume will be either large or small.
This affects the test time interval in #3.
As well as all the conditions, each time the Tank is opened.
.
Why the test is done?
To test Check Valve sealing when (not) under Turbo Boost conditions, the Check valve does not >>Leak boost pressure into the fuel tank under Boost conditions later.
.
The test is actually done under non-Boost conditions ahead, and not under Boost conditions. #1.
Replace all the lines and >check valves< to be sure they seal, because you can't do any meaningful testing due to the complexity of the system, its parts, and complexity of the test, itself.
The Pressure Sensor in the TANK is used to report the failure or success.
Good luck.

 

Thanks
I am throwing in the towel and got an appt next tuesday at the dealer. I know what you all are thinking...lol, I hate the dealers also. I have checked all the hoses and they seem good, the schuttle valve on the EVAP assy seems good and the EVAP valve is closed at engine start and starts to open after about 5 min. But with my limited time schedule at home I need this at least troubleshoot better if possible. I Will update when I have more info. Hopefully this will help someone else.
thank you all for all the info. I have learned alot about what I don't want to learn...LOL

 

Another Update
the dealer said the EVAP valve is bad. that would mean that the last 2 from Napa in 60 days were bad. The new one from the dealer will be here friday so I shall see then. I have my doubts. When I tested the valve myself it would be closed with engine started and opened after about 5 minutes and the shuttle valve also seemed fine.
will see friday. Their diagnostic machine print out all tested good except for the valve he said

 

Installed the nerw dealer EVAP valve and so far so good. Not 100 percent convinced yet. will need to go a couple of weeks. but before the CEL would come on very shortly after reseting, now it is staying off. we will see
Larry

 

I bought a Dorman replacement online a few weeks ago. Was that the brand yours was that you bought from NAPA? I think I may just order an OEM one as well. I'm in the same boat as you. I've spent several nights checking all the hoses and maybe we should have both just went for the OEM part. Maybe the aftermarket parts aren't built exactly right.