P0171 Need Help

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gsrakka

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I have a 2004 Ford Expedition 4.6L with 114000 miles and about a month ago check engine light came on. Code reader picked up P0171. The SUV runs fine but at idle the engine shakes a little. The LT FTRM1 is around 24%. Took to my mechanic and he was unable to narrow down the problem. Took it to Ford dealership and after a week they came back and said it has jumped timing. They want to charge almost $2000.00 to open up take a look and put back together. Below is what has been done or ruled out as an issue

My Mechanic
1. Replaced O2 Sensor (Bank 1)
2. Replaced MAF
3. Replaced Air Filter
4. Replaced Spark Plugs
5. Cleaned Throttle Body

Ford
1. Replaced O2 Sensor (Bank 2)
2. Verified no vacuum leaks, engine compression is good, engine computer is good.

Should I try?
1. Replace DPFE
2. Replace EGR Valve
3. What else can I try?
My mechanic had my SUV for 3 weeks, Ford had it for a week. Luckily my mechanic did not charge me for all he did. Ford is going to charge me for O2 sensor for bank 2 but that is still a conversation to have with them.
I have searched for P0171 code but most what I can find are P0171 and P0174 combination.
 
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Bedrck47

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You say the throttle body was cleaned. Was the TB removed and the YWO exhaust ports in the TB cleaned?

check the attached links

http://www.expeditionforum.com/f42/about-egr-pcv-dpff-evap-iat-tps-maf-23583/#post191356

Part 1 -Troubleshooting P0171 and P0174 (Ford 4.6L, 5.4L)

copied from the Ford service manual

Diagnostic Trouble Code
P0171 - System Too Lean (Bank 1)

Descriptions
The adaptive fuel strategy continuously monitors the fuel delivery hardware. The test fails when the adaptive fuel tables reach a rich calibrated limit. Refer to Section 1 , Powertrain Control Software, Fuel Trim for more information.

Possible Causes

Fuel System.
Fuel pressure regulator (leaking, faulty).
Fuel filter plugged, dirty.
Fuel pump (weak, check valve leaking).
Leaking/contaminated fuel injectors.
Low fuel pressure or running out of fuel.
EVAP canister purge valve leaking (when the canister is clean).
Fuel supply line restricted.
Fuel rail pressure sensor (incorrect reading).

Air Induction System.
Air leaks after the MAF.
Vacuum Leaks.
PCV system (leak or valve stuck open).
Improperly seated engine oil dipstick.

Exhaust System.
Exhaust leaks before or near the HO2Ss (exhaust manifold gasket, mating gaskets).

EGR system.
Vacuum hose disconnected on EGR System Module (ESM) applications.
EGR valve tube/gasket leak.
EVR solenoid vacuum leak.

Secondary Air Injection.
Damaged/malfunctioning secondary air injection system (mechanically stuck valve).

Air Measurement System.
MAF sensor (contaminated, damaged, or faulty).

Diagnostic Aids
View Freeze Frame Data to determine the operating conditions when the DTC was set. Observe the LONGFT1 and LONGFT2 PID(s). Refer to Section 2 , Adaptive Fuel DTCs Diagnostic Techniques for more information.

check youtube for this video
P0401 code ford Throttle body EGR port cleaning 4.6 Ford Expedition part 1 of 5
 
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gsrakka

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I checked with my mechanic and the throttle body was not removed and cleaned. I plan on doing that myself this weekend.
 
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gsrakka

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Throttle body and all ports have been cleaned. Fuel pressure tested and has passed. Replaced PCV valve and EGR. Tested for vacuum leaks and none found using the smoke test.

ST FTRM1 -3.1
LT FTRM1 29.7
ST FTRM2 -0.8
LT FTRM2 -11.7

Does this mean its lean on 1 side and somewhat rich on the other side?
 

the bus

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Check the fuel pressure in the rail. Also do not over look the vac elbow on the back of the intake. 9" of 5/8 heater hose can be a quick change or test.
 

Bedrck47

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Check the fuel pressure in the rail. Also do not over look the vac elbow on the back of the intake. 9" of 5/8 heater hose can be a quick change or test.

This thread has bee inactive since May and this is typical of many new members They come on ask for help, get some responses, and then they disappear without even a Thank You
 
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gsrakka

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I apologize Bedrck47. I should have posted back and said thank you. After all of this, it was still having the same issue. 2 other mechanics had reached the same conclusion as Ford that the timing belt had jumped. I cut my losses on trying to keep throwing money at it and traded it in. I truly appreciate you help and thank you.
 
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