Everything started with the typical lean bank 1 and bank 2 codes.
I started at the basics change fuel filter PCV Hose & Valve clean the MAF changed air temp sensor(it was cheap)
Still had same po171&po174 codes. Bought a obdll reader. After 3 weeks of nothing being accomplished I bit the bullet and took it to Ford for a diagnostic and they said it was definitely the intake gaskets.
I changed the gaskets and now this has gotten worse!
I started the truck after reassembly and it ran like crap!
Checked everything and everywhere and could find nothing wrong. I then took off the vacuum line to the EGR and everything smoothed out. I didn't mess around and replaced the EGR the DPFE and the vacuum solenoid.
It still runs like crap especially at idle. I did the tests with my digital meter and found the vacuum solenoid is calling the EGR to be open all the time. I suspect that this would be the fault of the PCM? What should be my next course of action?
Seg289

 

Identify WTF you're working on, we're not psychic.

Test the DPFE sensor.

 

Follow along so we can get to the root cause even though you did your testing.
Remove the electrical connector from the EVR.
If the idle smoothest out the EVR was operated.
If not, the hoses are reversed or the EVR is 'stuck open', leaking vacuum by itself.
The EVR has voltage on it and waits for a ground from the PCM.
The EVR is actually a 3 port device. Vacuum in , output port and a bleed down port under the round cap that has a filter under it.
If it shows operated you can check for the ground. Be sure the harness is not grounded at some point.
An electrical issue is normally picked up be the PCM diagnostics.
Are you sure there are no codes.
This should be easy to pin point.
.
The 171/174 codes point to an air leak into the intake tract.
This is verified by looking at the long term fuel trim tables being shifted more then 25% trying to account for the air leak. Use of a Scanner is required to see them.
Check out all the hoses for being correctly hooked up.
Check out the PCV hose and ELL behind the vertical intake for deterioration.
Leave everything else alone.
Good luck.

 

Thanks for responding guys! Just to let you know this is a 02 f150 5.4L King Ranch 2v
I thought this would be easy to pin point too!
Nothing changes in the way it runs with or without the EVR electric connector on or off. Thought this to be very strange. The two vac lines are impossible to put on wrong because it is a one piece molded connector. The pcv hose assembly is brand new from Ford so I know it's not the rear elbow. After I started the truck I got the po401 code. That's when I changed all the EGR components ie.
EGR, DPFE AND EVR. The truck has 225,000 miles and I have had it for about 2.5 years. The whole thing started when I jumped on it on the freeway to pass a idiot going 50 in the fast lane. I am old school and have a pretty good idea about electronics but this just doesn't make sense to me. Oh I also have the AEM after market intake. I run a dry air filter so no oil like K&N uses. Any ideas?

 

Are you saying that, with the EVR electrical connector disconnected, that you still have vacuum passing through the EVR valve to the EGR valve? If the EVR valve is passing too much vacuum uncommanded, it's bad, regardless of its age.

 

I got the EGR working correctly and the truck is running much better now so thanks for your help!!
I erased the codes and drove the truck it is running good but after about 20 miles I got the SEL again the codes were 0171 & 0174 lean codes again. I changed the intake gaskets and the throttle body gasket per the diagnosis of the local Ford dealer. I checked for vacuum leaks with carb spray and found nothing. All is tight.
No other codes came up. The Ford dealer cleaned the throttle body they said and it was clean when I reinstalled it. The engine is not missing like an injector is malfunctioning. I am banging my head against the wall trying to get this solved. It's like I am back at square one.
Any suggestions. I don't have a fuel pressure tester is there anyway to test without one. Fuel filter was the first thing I changed when the lean codes first appeared.

 

Now you have one item solved now go on to the air leak.
I will tell you point blank, the codes do not lie.
You have an air leak your missing yet.
The OX sensors detect too much Ox left in the exhaust 'after' combustion.
The 'nose' knows like it's designed to do.
The long term fuel tables will verify this.
The codes are for both banks so the leak is common to both banks, as a hint..
Good luck..

 

And what was that issue? Please follow up.


If you were doing the old-school trick of spraying and listening, that rarely (if ever) works on a modern computer-controlled engine. The computer is simply too fast.

You have to hook up a scan tool and monitor either the short term fuel trims or the O2 sensor voltages and observe THEM while sprayin' and prayin'. It works.