Ford

Have Ford questions? Ask a mechanic for answers ASAP

Ask an Expert,
Get an Answer ASAP!

This answer was rated:

Codes P0171, P0174. I clear codes, they come back after

about a week. No drivability...
Codes P0171, P0174. I clear codes, they come back after about a week. No drivability problems at all. Smooth idle, no apparent vacuum leaks that I can hear or notice spraying around with carb cleaner.
Show More
Show Less
Ask Your Own Ford Question
Customer reply replied 4 months ago
2005 Ford F 150, V-6. 75K miles.
Answered in 11 minutes by:
3/14/2018
A. Penland
A. Penland, Ford Senior Master Technician, ASE
Category: Ford
Satisfied Customers: 6,958
Experience: ASE Master Certified, ASE Advanced Gasoline Engine Performance
Verified

The leans codes can be caused by a vacuum leak, contaminated Mass Air Flow Sensor, sticking Evaporative Emission Purge Valve or low fuel pressure.

Since you do not have any drivability issues, low fuel pressure is not the problem.

The most common causes we have seen are the intake manifold rubber O-ring seals that seal the upper intake to the lower.

But check the MAF sensor. You can clean it with CRC Mass Air Flow Sensor Cleaner that auto parts stores sell.

Ask Your Own Ford Question
Customer reply replied 4 months ago
O.k., I'll start with cleaning the MAF. The intake o ring seals only require pulling the upper intake manifold?

Yes. Just the upper intake needs to come off. The rubber o rings harden up over time and do not seal fully.

After cleaning the MAF, disconnect the battery for 10 minutes to reset the PCM (Engine Computer) memory.

A. Penland
A. Penland, Ford Senior Master Technician, ASE
Category: Ford
Satisfied Customers: 6,958
Experience: ASE Master Certified, ASE Advanced Gasoline Engine Performance
Verified
A. Penland and 87 other Ford Specialists are ready to help you
Ask your own question now
Customer reply replied 4 months ago
O.k., thanks!

Your welcome. Thank you.

Ask Your Own Ford Question
Was this answer helpful?

How JustAnswer works

step-image
Describe your issueThe assistant will guide you
step-image
Chat 1:1 with a ford mechanicLicensed Experts are available 24/7
step-image
100% satisfaction guaranteeGet all the answers you need
Ask A. Penland Your Own Question
A. Penland
A. Penland
A. Penland, Ford Senior Master Technician, ASE
Category: Ford
Satisfied Customers: 6,958
6,958 Satisfied Customers
Experience: ASE Master Certified, ASE Advanced Gasoline Engine Performance

A. Penland is online now

A new question is answered every 9 seconds

How JustAnswer works:

  • Ask an ExpertExperts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional AnswerVia email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction GuaranteeRate the answer you receive.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

AlvinC answered a question about my Ford truck that only someone with an in-depth knowledge of his subject would have known what was going on.

Rich DUSA

Because of your expertise, you armed me with enough ammunition to win the battle with the dealer. They are installing a fuel filter and fuel pump at no charge to me.

MollyUSA

I needed help with my car on Saturday morning....got a response in 5 minutes, and it was the perfect solution. Thanks again to your service.

Jason V.Kirkland, WA

I do know, after going though this with JustAnswer, that I can somewhat trust my mechanic but I will always contact you prior to going there.

BRNew Jersey

I would (and have) recommend your site to others I was quite satisfied with the quality of the information received, the professional with whom I interacted, and the quick response time. Thanks, and be sure that I'll be back whenever I need a question answered in a hurry.

Stephanie PElm City, NC

used your service this weekend with "Trecers" help. thank you ,thank you, thank you. replaced an A/C fan motor. Local Auto Zone had part. $15.00 "tracer" fee and $40.00 for parts, I saved several hundreds of dollers at a shop. i will recommend you and use you in the future.

David L.Richmond, TX

9 dollars, 2 hours of my time, and I drove away. Your diagnosis was right on the mark. Thank you so much.

PhilMarysville, CA

< Previous | Next >

Meet the Experts:

Ron

Ron

ASE Certified Technician

25,022 satisfied customers

23 years with Ford specializing in drivability and electrical and AC. Ford certs and ASE Certs

Chris (aka- Moose)

Chris (aka- Moose)

Technician

28,993 satisfied customers

16 years experience

John Mc

John Mc

Ford Technician

5,495 satisfied customers

19 years Ford Lincoln Mercury experience

Chuck

Chuck

ASE Certified Technician

1,685 satisfied customers

33 Years Experience,Ford Senior Master,ASE Master,L1 Advanced Engine Performance

Cam

Cam

Journeyman Automotive Technician

10 satisfied customers

GM Grand Master Technician 2007. 14 years Automotive experience.

Mike V.

Mike V.

Auto Service Technician

1,556 satisfied customers

25 years experience on all makes and models, Licensed NYS Inspector.

Richard

Richard

ASE Certified Technician

1,524 satisfied customers

12 years at a Ford Lincoln/Mercury and Jaguar dealer as a technician and shop foreman.

< Previous | Next >

Related Ford Questions
F150: Im working on a potential vacuum issue on a 1997 Ford
I'm working on a potential vacuum issue on a 1997 Ford F-150 Lariat Edition w/ 5.4L Triton, 4x4, 165k+ miles. I keep getting codes P0171 and P0174 and the indicated vacuum pressure is around -10 psi a… read more
Ron
Ron
ASE Certified Technician
Vocational, Technical or Trade Scho
25,022 satisfied customers
2003 FORD E 150: vin..SMOOTH..NOW THE CHECK ENGINE LIGHT CAME
HI MISTER TECH, MY NAME ISXXXXX HAVE A 2003 FORD E 150 4.2L VIN #1FTRE14263HB25102. I'VE REPLACED THE MASS FLOW SENSOR (ORIGINAL FORD) ON IT ABOUT 2 MONTHS AGO, BUT THE VAN NEVER WORKED SMOOTH AND NOW… read more
chris
chris
Ford tech at a dealer
Associate Degree
2,764 satisfied customers
1998 F-150: check engine..first start..mile or two, it runs fine
I have a 1998 F-150 and the check engine came on. When I first start the engine and drive a mile or two, it runs fine. After that, it runs really rough. Went to Auto Zone and their meter said it's eit… read more
Chris (aka- Moose)
Chris (aka- Moose)
Technician
Vocational, Technical or Trade School
28,993 satisfied customers
2001 Ford F-150: XLT..cylinder..check engine light..acceleration
2001 Ford F-150/XLT six cylinder Trouble Codes P0171 and P0174 with check engine light of course. Engine pings mildly on acceleration so this probably cinfirms that it is running lean? Interested in d… read more
eauto
eauto
self employed
High School or GED
74 satisfied customers
1999 ford: o2 sensors..check engine light came..egr
i have a 1999 ford e150 with 4.2L wont pass emissions test, i replace both up stream and both down stream O2 sensors cleared codes and test. check engine light came back on with codes P1401(DIFF PRESS… read more
Paul M ASE Master
Paul M ASE Master
Automotive College
3,307 satisfied customers
2001 ford f 150: idles rough..park..i did the coils and plugs..p0171
2001 ford f 150 idles rough when in park and worse in drive. i did the coils and plugs about eight months ago and i just replace the mass airflow sensor couple days ago because i thaught it was that, … read more
A. Penland
A. Penland
Ford Senior Master Technician, ASE
Vocational, Technical or Trade School
6,958 satisfied customers
1997 f-150: P0171..P0174..liter engine..these codes coming up together
I have a 1997 f-150 Ihave code of P1506 Also P0171 and P0174 4.2 liter engine. What would be the comen thing about these codes coming up together?… read more
Eric
Eric
Retired
N/A
14,436 satisfied customers
2001 ford f-250: runs rough..p0171 and p0174 (lean Banks..runs good
my 2001 ford f-250 superduty runs rough when I start it for about a minute Then clears up I get p0171 and p0174 (lean Banks) cleaned the mas no help it runs good after it runs a bit but still not The … read more
CTFordTech
CTFordTech
Auto Technician
Vocational, Technical or Trade Scho
4,460 satisfied customers
2005 Ford F350: air filter..OBDII codes for lean..ECM..O2 sensors
Changed a real dirty air filter on 2005 Ford F350 with V-10 engine;95M miles; now have OBDII codes for lean: P0171, P0174, P2195 & P2197. Will ECM correct this after clearing codes or is it time to R&… read more
Dennis
Dennis
Senior Master A Technician/Shop Foreman
Vocational, Technical or Trade Scho
758 satisfied customers
2001 Ford F150: V6..wheel drive..cleaner..popping , misfiring
hi I have a 2001 Ford F150 4.2 V6XXXXXgot codes P1401 P0171 and P0174 changed DPFE cleaned MAF sensor with crc contact cleaner new Plugs and wires still hesitates when taking off and sounds like poppi… read more
Chris (aka- Moose)
Chris (aka- Moose)
Technician
Vocational, Technical or Trade School
28,993 satisfied customers
98 Ford Expedition 4x2: 5.4L..Triton..Its idling rough after it warms
I have a 98 Ford Expedition 4x2 5.4L Triton engine. It's idling rough after it warms-up. Check engine light it's on. The scanner showed a P0171 and P0174. I changed all four O2 sensors, the MAF and on… read more
Richard
Richard
ASE Certified Technician
Vocational, Technical or Trade Scho
1,524 satisfied customers
1997 ford f-150: have code keeps popping up po171..i changed o2 sensor
i have 1997 ford f-150 have code keeps popping up po171. i changed o2 sensor ,but come on again .do you any suggestions… read more
Eric
Eric
Retired
N/A
14,436 satisfied customers
2000 Ford Taurus: Wagon..P0171..P0174..possible causes and course
2000 Ford Taurus Wagon with 75K miles has codes P0171 and P0174. I was told these mean engine is running lean. What are possible causes and course to fix them?… read more
Richard
Richard
ASE Certified Technician
Vocational, Technical or Trade Scho
1,524 satisfied customers
ford f-150: codes p0171, and p0174, System too lean bank 1
I have a ford f-150, 5.4 L engine, have codes P0171, and P0174, System too lean bank 1, and 2. What does this mean?… read more
Jim
Jim
Service Manager
High School or GED
260 satisfied customers
I have an OEM of P0171 and P0174 on my ford F-150. I ...
I have an OEM of P0171 and P0174 on my ford F-150. I have replaced the MAF senor but the check engine light is still on. What next?… read more
Fordster
Fordster
Mastertech
Vocational, Technical or Trade Scho
2,650 satisfied customers
1998 Ford windstar: my engine light..3 of them, p0306, p0171, p0174
I have a 1998 Ford windstar 3.8 engine, my engine light is on and I check for codes and i got 3 of them, P0306, P0171, P0174, can someone help me… read more
Mike V.
Mike V.
Auto Service Technician
Subaru and Nissan factory training.
1,556 satisfied customers
1999 Ford Exp: P0171..P0174..IAC, MAF Sensor, Air Filiter
1999 Ford Exp is idling rough and has codes P0171 and P0174. Replaced IAC, MAF Sensor, Air Filiter. What is wrong with it?… read more
Chris (aka- Moose)
Chris (aka- Moose)
Technician
Vocational, Technical or Trade School
28,993 satisfied customers
FORD EXPLORER: 4X4..CHECK ENGINE..GIVES ME THIS CODES: P0171 AND P0174
i HAVE A FORD EXPLORER 2000 4X4 AND CHECK ENGINE ON THE COMP. GIVES ME THIS CODES: P0171 AND P0174. WHAT COULD THAT BE ?>???… read more
LBS Tech
LBS Tech
Ford Technician
Associate Degree
198 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x