I cleaned it the day before the test but I'll try cleaning it again, motorcraft pcv will be here tomorrow, Friday, so stay posted.

 

That was relevant and should have been reported days ago....

 

So just try replacing the PCV now?

 

Just replaced the MAF with a motorcraft one, no change, just replaced the PCV and the rubber grommet with a motorcraft one, no change... Where to next? I plan on doing my oxygen sensors this weekend, I know you guys said I'm waiting my money and time on them, but it's part of routine maintenance and tune ups so I figured may as well change them and see if that makes any difference.

 

 

Id say no. I cleared the check engine light just before I replaced maf and pcv, then hit record live data on my reader, then went for a drive. Long term fuel trim is just as high as before and maf reading the same values

 

Id say no, I cleared the CEL before I replaced maf and pcv, live data shows the truck will throw lean codes again since the long term fuel trim goes over 10 under load. Ill post fuel pressure on Monday when my gauge comes in

 

Checked the fuel pressure, 30 before it started, ran at 30, when I pushed on the gas it dropped down to 25

 

FP should be 35-45 psi at KOEO, 28-45 psi KOER per factory service manual.

 

 

I'm thinking fuel pressure regulator?

 

Nonsense. I was pretty clear about that previously.

 

So do you think fuel pressure regulator? Injectors? Pump?

 

I notice in your video - THE PCM IS STILL IN "OPEN LOOP". ProjectSHO89 pointed this out in his initial response.


He ALSO said about vacuum leaks...

Definitely not "always", but usually, probably 90% of the time. Low fuel supply or a MAF that is mis-reporting the intake air charge will also cause "lean" codes on both banks.

AND... he ALSO said this is why we do diagnostics.

B U T, the diagnostics must be done in a way that will be helpful. The Fuel Trims, Fuel Pressure, Intake Air ---- and everything else is basically meaningless when the PCM is in "OPEN LOOP". The very meaning of OPEN LOOP is that the PCM is using 'factory default' values for injector pulse width, NO MATTER WHAT the upstream O2 sensors are reporting. (I do not know if the PCM even stores the fuel trim values in the fuel trim table under OL condition".)

So anything we determine is pretty much an 'ASSUMPTION'. You need to get it in Closed Loop, or figure out WHY it will not go into CL first.

As to vacuum leaks - in addition to the items @ProjectSHO89 mentioned, an exhaust leak ahead of the O2 sensor will also give lean codes, (though unlikely on both banks). A leak in the EGR valve diaphragm will produce lean codes in the RPM/LOAD range (light cruise range) where the PCM calls for exhaust gas recirculation. Freeze Frame data would be a useful indicator in this respect --- ie: what were other conditions WHEN THE DTC IS SET.

Once you have it going into Closed Loop, I think a much more reliable method of checking for vacuum leaks is to monitor live STFT1 and STFT2 data while using an unlit propane torch and blow propane all around all possible leak points. When you get -even close- to a vacuum leak, fuel trims will go WAY NEGATIVE - immediately. If you don't believe it, just pass a little in front of the air intake.

Hope these thoughts help.

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EDIT: The 'video' I referenced was the second one - not most recent ones, but my point (though not clear) was to reinforce the importance of those sort of details that often color our diagnostic decision.