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Old 02-01-2016, 11:57 PM   #1
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Code P0171

Hey everyone I'm a new member. And I'm having an issue with code P0171 system too lean bank 1 on my 2004 GT. This code has been coming on and off by itself for 6-8 months now. I know it's the passengers side. I recently changed the intake manifold because it was leaking at the heater core. I also changed all these parts to freshen up the engine and hopefully get rid of the code. I need help with identifying where all the vacuum hoses are on this car.. TIA
PCV Valve
Camshaft positioning sensor
Crankshaft positioning sensor
idle air valve control
Throttle body positioning sensor
MAF
PCV to upper intake vacuum hose
Exhaust Gas Recirculation Pressure Feedback Sensor
Front o2 sensors
Fuel injectors
CAI filter


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Old 02-02-2016, 01:31 AM   #2
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Carefully inspect for any vacuum leaks... Particularly, recheck all of the recent work that you've done.
Also inspect for any exhaust leaks on bank one.
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Old 02-02-2016, 12:06 PM   #3
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Where is that egr feedback sensor located at any pics?


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Old 02-02-2016, 05:14 PM   #4
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So I took the car in to be leak tested with the smoke machine. NOTHING.. Lol car is solid with no leaks on the vacuum lines. They did notice some some leaking out of where the CAI housing meets the MAF meter. They said that was the cause. So I siliconed everything. Your guys thoughts on that?


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Old 02-02-2016, 05:59 PM   #5
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Well that would still be a vacuum leak see how it does with repair

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Old 02-04-2016, 08:07 PM   #6
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Thanks so I did the silicone thing and I also changed the fuel rail pressure sensor. Still getting the same thing. Do you think it could be the CAI? Mine sits inside the fender well. Should I try one that sits inside the engine bay?


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Old 02-04-2016, 08:48 PM   #7
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Or lastly I would change the fuel pump.. Only other thing I could think of


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Old 02-04-2016, 10:09 PM   #8
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Do a fuel pressure test before you replace the pump.
The fuel pressure at idle should be 40-70 psi. The fuel system should hold pressure for five minutes after turning the engine off, and it shouldn't lose anymore than 5psi from the indicated operating pressure.
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Old 02-04-2016, 10:14 PM   #9
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Ok perfect. I'll try that over the weekend. Tomorrow morning I'm going to the ecu reset and idle re learn.


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Old 02-06-2016, 01:39 PM   #10
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My fuel pressure was a steady 42 PSI.. Which is good I'm told.. I'm now leaning towards the ECM needing replacement.


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Old 02-06-2016, 08:28 PM   #11
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Well, I guess that the only thing, on the list of P0171 symptoms, that you haven't replaced is the EGR valve itself. I think that the EGR tube can become clogged and cause problems as well.
The odds are not very good that the EGR is at fault though... I would test the EGR and see if the tube is clogged before replacing it.

Are you positive that you have repaired any vacuum leaks at the air intake?
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Old 02-06-2016, 10:09 PM   #12
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I've replaced The EGR valve.. The code comes back with 10 miles of ever clearing it... I'm confused on what's else to do...


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Old 02-06-2016, 11:47 PM   #13
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Oh. Ok. I wasn't sure, from your first post, , if you had replaced the EGR or the sensor... I presume that you have replaced both.

At this point, I think that I would just swallow my pride and have the car professionally diagnosed by a knowledgeable shop. And depending on what they find to be the problem, maybe even let them do the repair so you would have a guarantee that the problem will be repaired.
You might call your local Ford dealership and ask them what they charge to do a diagnostic check for your code.
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