codes P0171, P0174 Lincoln LS V6"

[gwells]

I got the engine check light a month or so and thought it was a case of bad gas but unsure now. It starting to stall at idle. Just stops with no warning. running like a kitten to off. Thanks.

Geoffrey Wells
2001 LS V6

[shorod]

P0171 is System Too Lean (Bank 1) and P0174 is System Too Lean (Bank 2). Per the service manual, these are some items to check:

• Fuel system
• Excessive fuel pressure.
• Leaking/contaminated fuel injectors.
• Leaking fuel pressure regulator.
• Low fuel pressure or running out of fuel.
• Vapor recovery system.
• Induction system:
  • Air leaks after the MAF.
  • Vacuum Leaks.
  • PCV system.
  • Improperly seated engine oil dipstick.
• EGR system:
  • Leaking gasket.
  • Stuck EGR valve.
  • Leaking diaphragm or EVR.
• Base Engine:
  • Oil overfill.
  • Cam timing.
  • Cylinder compression.
  • Exhaust leaks before or near the HO2Ss.

I think this subject has come up before on this forum. You may want to use the search feature for this forum and see what other's have found to resolve the issue.

When you determine your problem, please post back with your resolution as well.

Good luck!

-Rod

[Quik_LS]

very common issue on the V6 - the little rubber elbow on the PVC wears through. Unfortunately it is a pain to get at - as it's under the intake manifold. Not too difficult for a DIYer, but working in cramped quarters.

[gwells]

Update. I have done the gas additive and no help. Also, checked PCV and no issues. I have borrowed a scantool called AutoEnginuity and have more data. It looks like the problem is at idle. Per the diag tool it shows:
P0171 System Too Lean (Bank 1)
Module: Fuel and Air Metering
Status: Stored
Freeze Frame (Frame 0)
Calculated Load: 28%
Coolant Temp: 203F
Engine RPM: 757 r/min
Fuel System Status Bank One: Closed Loop
Fuel System Status Bank Two: Not Reported
Long Term Fuel Trim Bank One: 24.96%
Long Term Fuel Trim Bank Two: 24.96%
Short Term Fuel Trim Bank One: 31.98%
Short Term Fuel Trim Bank Two: 28.86%
Vehicle Speed: 0 MPH
P0174 System Too Lean (Bank 2)
Module: Fuel and Air Metering
Status: Stored

[Towncar]

On my Town Car (same two codes), after going through EVERYTHING else first, I found the MAF sensor to be the culprit.

Pulled it out, it was absolutely filthy, cleaned it up, reset the OBD system, no problems after that.

[gwells]

That piece looks fine. I am going to check the EGR vavle next.

[gwells]

Ok. I went to the lcal Auto Zone and they don't carry LS book. Where is the EGR valve located and who carries a Chilton like book for the 2001 LS?

[gwells]

Bought the repair CD for 2001 Ford models and found the Fuel filter. Replaced. No help brought to Good year $50 for diagnosis and Fuel pump is 98% issue. machanic said 8 psi fuel levels and my new manual shows 30-65 psi. looking at $230 for new lifetime. I will let all know if it is problem.

[Towncar]

Originally Posted by gwells

...looking at $230 for new lifetime. I...

OUCH !!

[mopar440man]

had the same problem i replaced the spark plugs , coil, valve cover gaskets and then it was still doing the same thing i took it to the dealship my uncle works at and they said the ecu needs to be replaced im still looking for a used on the new one is 800 to have them put it in

[GFORCEBOYS]

I Have A 2000 Ls W/130000+ Miles Had Car For 2 Years No Problems Till 3wks Ago P0171/p0174 Took Apart Intake Manifold Found 2 Oil Soaked Plugs 4 Spark Plug Boots Sweled Pcv Was Verey Dirty Elbow From Pcv Was Cracked Egr Valve Was Also Verey Dirty Throtell Body Dirty. Replaced Plugs/pcv Valve/spark Plug Boots/ Broken Elbow From Pcv Valve /cleaned Throtell Body /egr Valve /put Fuel Injector Cleaner Waiting On 1 Part From Dealer To Check And See If Problem Solved. Not Any Easy Task If You Your Not Mechanicly Inclined Any Qustions Ask

[Stylez850]

I'm about to give up on this car now. I also have a 2001 ls v6. I'm having alot of the same problems. When it idles for more then 3 seconds it will start to shake like a cylinder was misfiring, then after about 30 seconds with out giving it any gas it will just cutoff. I've noticed that the rpms gauge will be jump lightly below the normal idle rpms. I've changed the spark plugs, the o2 sensors and it still happens. Just got it back from the dealership and they are telling me that I have lean codes on both banks, misfire codes, and egr codes. One things they were able to identify was a vacuum leak coming from connection at rear of engine under lower intake and egr vacuum regulators resistance is out of range. They still don't know what would happen if those two things get fixed. Hopefully somebody might be able to give me more insight before I lose it and blow that thing up . Over here in hawaii it will cost $826 just to change those two things so another issue is breakin' my bank. Thank you guys

[shorod]

Sounds like the vacuum leak they were able to identify is the PCV elbow, which appears to be a pretty common issue on these. I changed the one on my wife's '02. It wasn't fun, but is possible with common hand tools. That would likely fix the lean codes. I suppose there is a chance that the vacuum leak is also preventing the EGR from working properly, but I wouldn't expect it to cause the regulator to report out of range. That seems like either a part issue (likely) or a wiring issue (less likely, unless your car spends a lot of time at the beach).

-Rod

[Stylez850]

I just changed the EGR vacuum solenoid and now it idles longer till it cuts off but will still rattle like a cylinder is misfiring. Would that vacuum leak cause the car to shake like a misfire and then cut off?

[Stylez850]

OH YEAH!!! Now that I changed that egr vacuum solenoid, I feel a stutter somewhere around 48 mph. That never happened until I changed that part. What is goin' on with this evil machine ??