Buick

Buick Repair Questions? Ask a Mechanic for Answers ASAP

Ask an Expert,
Get an Answer ASAP!

Rough idling, misfires and has trouble starting after

Customer Question
Rough idling, misfires and...

Rough idling, misfires and has trouble starting after filling the tank. Error codes thrown are P0170, P0171, and P0506.

Mechanic's Assistant: Is the rough idle intermittent or consistent?

Consistent not super rough Check engine light is on. Main symptom is trouble starting after filling up.

Mechanic's Assistant: What is the model/year of your Buick?

2012 Buick LaCrosse Touring model 3.6 engine

Mechanic's Assistant: Are you fixing your LaCrosse yourself? What have you tried so far?

Yes. Replaced the MAF sensor.

Submitted: 7 months ago.Category: Buick
Show More
Show Less
Ask Your Own Buick Question
Answered in 8 minutes by:
12/7/2017
Buick Mechanic: Jared D, ASE Certified Technician replied 7 months ago
Jared D
Jared D, ASE Certified Technician
Category: Buick
Satisfied Customers: 2,277
Experience: Shop Supervisor at County Fleet
Verified

Good morning,

Does it act like that every time you fill the tank or did it just start doing it since you filled the tank?

Ask Your Own Buick Question
Customer reply replied 7 months ago
Every time I fill up.
Buick Mechanic: Jared D, ASE Certified Technician replied 7 months ago

How many miles do you have?

Ask Your Own Buick Question
Customer reply replied 7 months ago
88K
Buick Mechanic: Jared D, ASE Certified Technician replied 7 months ago

That doesn't seem like enough miles to suspect a failed high pressure fuel pump.

We usually see those codes when the fuel injectors are plugged also, but filling the tank wouldn't really affect that. Once the fuel level drops it seems to smooth out?

Ask Your Own Buick Question
Customer reply replied 7 months ago
It's only a problem starting when I turn the car on after filling up. It starts fine every time after that.
Buick Mechanic: Jared D, ASE Certified Technician replied 7 months ago

Ok. That sounds like a bad fuel tank pressure sensor. It's a sensor in the fuel pump assembly. It usually throws a different trouble code, but that's the symptom you get when it isn't working correctly.

Ask Your Own Buick Question
Customer reply replied 7 months ago
Plus I didn't get any of these codes
Related OBD Codes
P228C - Fuel Pressure Regulator 1 Exceeded Control Limits - Pressure Too
P228D - Fuel Pressure Regulator 1 Exceeded Control Limits - Pressure Too
P228F - Fuel Pressure Regulator 1 Exceeded Learning Limits - Too High
P228E - Fuel Pressure Regulator 1 Exceeded Learning Limits - Too Low
P0089 - Fuel Pressure Regulator 1 Performance
P229A - Fuel Pressure Regulator 2 Exceeded Control Limits - Pressure Too
P229B - Fuel Pressure Regulator 2 Exceeded Control Limits - Pressure Too
P229D - Fuel Pressure Regulator 2 Exceeded Learning Limits - Too High
P229C - Fuel Pressure Regulator 2 Exceeded Learning Limits - Too Low
P2293 - Fuel Pressure Regulator 2 Performance
Buick Mechanic: Jared D, ASE Certified Technician replied 7 months ago

What sort of scan tool do you have?

You'd only see those codes with a Tech 2.

Ask Your Own Buick Question
Customer reply replied 7 months ago
I take it to the military base auto shop and they use their scanner. Error codes are P0170, P0171, P0506.
Customer reply replied 7 months ago
I have none of the symptoms that equate to a bad ftp when I looked it up:
1. Black Smoke Emitting from the Tailpipe-2. Gasoline Runs Out of the Tailpipe-3. Engine Not Running Smoothly-
When you’re idling at a light or before putting your vehicle in gear and you notice your engine making unusual noises, change your oil filter and also check the pressure regulator to try and fix the problem. If you have trouble getting your car to start and notice it not turning over immediately, it can also signal a bad fuel pressure regulator.4. Stalling Engine-
If you notice that when you push your gas pedal down that your vehicle stalls then that could be an indication that the fuel pressure regulator is bad. When you accelerate you should have absolutely no hesitation and your car should begin to move immediately. If you begin to notice even a little hesitation when you attempt to accelerate, it could be an early sign of your fuel pressure regulator beginning to go bad.5. Issues When You Decelerate-
Buick Mechanic: david craig, ASE Certified Technician replied 7 months ago
david craig
david craig, ASE Certified Technician
Category: Buick
Satisfied Customers: 5,808
Experience: owner/mechanic at 3D Automotive
Verified

Its an electronic throttle control problem, it is lagging behind the commanded position causing not only p0506 but the lean codes also

Ask Your Own Buick Question
Customer reply replied 7 months ago
Are there any confirmatory tests I can do to prove that's the issue?
Customer reply replied 7 months ago
I don't have any of these issues that they say are associated with a throttle control problem:Vehicle may hesitate, misfire, or jerk on acceleration
Have difficulties changing gears
Display uneven power characteristics
Stall without any apparent reason
Experience sudden surges in speed while driving
Flashing check engine light
Severe drop in fuel economy
Customer reply replied 7 months ago
Can you tell me a bit more why you think it's a throttle control problem?
Was this answer helpful?

How JustAnswer works

step-image
Describe your issueThe assistant will guide you
step-image
Chat 1:1 with a buick mechanicLicensed Experts are available 24/7
step-image
100% satisfaction guaranteeGet all the answers you need
Ask Dave Nova Your Own Question
Dave Nova
Dave Nova
Dave Nova, Buick Technician
Category: Buick
Satisfied Customers: 1,808
1,808 Satisfied Customers
Experience: ASE Master Certification. GM World Class Certification

Dave Nova 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:

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

Mary C.Freshfield, Liverpool, UK

This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!!

AlexLos Angeles, CA

Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult.

GPHesperia, CA

I couldn't be more satisfied! This is the site I will always come to when I need a second opinion.

JustinKernersville, NC

Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around.

EstherWoodstock, NY

Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know.

RobinElkton, Maryland

He answered my question promptly and gave me accurate, detailed information. If all of your experts are half as good, you have a great thing going here.

DianeDallas, TX

< Previous | Next >

Meet the Experts:

Dave Nova

Dave Nova

Buick Technician

1,808 satisfied customers

ASE Master Certification. GM World Class Certification

Gary

Gary

Buick Technician

1,541 satisfied customers

15 years master GM tech and mater ASE tech

John

John

Buick Master Technician

731 satisfied customers

ASE A1-A8 w/L1 GM master technician.Factory certified with 40 years experience.

George H.

George H.

ASE Certified Technician

536 satisfied customers

ASE Master 15+years

Don - Mo Lurch

Don - Mo Lurch

Buick Mechanic

535 satisfied customers

GM, Chevrolet Cert., Heavy Line Mech, Race Shop Owner, Mobile Electronics.

Ron Z.

Ron Z.

- Buick Tech -

497 satisfied customers

18+yrs experience. State Inspector and Buick Diagnostics

Chris (aka- Moose)

Chris (aka- Moose)

Buick Technician

378 satisfied customers

16 years of experience

< Previous | Next >

Related Buick Questions
Random rough idle and dies. Intermitten. Replaced maf and
replaced maf and throttle position 1995 buick park avenue … read more
rpmdiag
rpmdiag
High school
7,774 satisfied customers
It is a 200 model Buick Century, car idles rough when
It is a 200 model Buick Century, car idles rough when stopped for a light. … read more
Ron
Ron
Automotive Tech
Vocational, Technical or Trade Scho
36,868 satisfied customers
02 sensor low voltage, random misfire bank one too lean,
02 sensor low voltage, random misfire bank one too lean … read more
Gunvir Singh
Gunvir Singh
1,949 satisfied customers
My engine light is blinking, Engine light was blinking on
Engine light was blinking on and off soon car would not pick up speed … read more
Gary
Gary
Buick Technician
Vocational, Technical or Trade Scho
1,541 satisfied customers
Engine is chugging already replaced coils engine light is on
engine is chugging already replaced coils engine light is on however the mechanic said I have air leak at the gas cap very rough idle smells different … read more
sprinkles08
sprinkles08
Technician
High School or GED
11 satisfied customers
2009 buick enclave. no trouble codes. misses randomly.
2009 buick enclave . no trouble codes . misses randomly . failed to start 2 times after putting gas in it until the accelerator was pushed . v 6 engine . 3.6 i think… read more
Brandon
Brandon
93 satisfied customers
I was driving on ice covered roads and tried to get up a
I was driving on ice covered roads and tried to get up a small hill but was having a hard time. All of a sudden I lost engine power, the car starts ok but I now have very limited power, What happened?… read more
sprinkles08
sprinkles08
Technician
High School or GED
11 satisfied customers
Its stalling right when it is started. it runs great the
its stalling right when it is started. it runs great the rest of the time but really rough starting … read more
Jake Cheek
Jake Cheek
23 satisfied customers
When driving along the the car will act as if it is missing
when driving along the the car will act as if it is missing and runs rough, then may run ok for a while.This is an intermittent problem. I noticed that after filling gas tank it is difficult to start,… read more
Chris (aka- Moose)
Chris (aka- Moose)
Buick Technician
Vocational, Technical or Trade School
378 satisfied customers
My car is losing antifreeze from a plastic tube leading from
My car is losing antifreeze from a plastic tube leading from the antifreeze fill to the motor. Would this tube be located underneath the motor? I was told they needed to get under the motor to change … read more
Roy Scarlett
Roy Scarlett
Occupational Education
17 satisfied customers
Check engine light came on went to auto zone and fuel rail
check engine light came on went to auto zone for OBDII and fuel rail pressure season was error code … read more
supermechanic
supermechanic
Service consultant
Vocational, Technical or Trade Scho
10 satisfied customers
Buick LaCrosse CX: I recently replaced the filter on my 2012
I recently replaced the filter on my 2012 Buick LaCrosse hybrid, now the vehicle keeps shutting down and will not stay on for more than a few seconds… read more
Gary
Gary
Buick Technician
Vocational, Technical or Trade Scho
1,541 satisfied customers
GM buick enclave: Under normal driving the stabilitrak comes
Under normal driving the stabilitrak comes on later the amber check engine comes on the code number is ***** I added brake fluid which has ended the stabiltrak message in the past but it just came bac… read more
Clayso
Clayso
Shop Owner Master Technician
ASE Master Certified Automobile Technician
879 satisfied customers
Buick Century Custom: This week my 1999 Buick Century has had
This week my 1999 Buick Century has had a very rough idle, especially in the mornings or after work when the engine has completely cooled down. Had a diagnostic performed and got error code P0171 erro… read more
Gary
Gary
Buick Technician
Vocational, Technical or Trade Scho
1,541 satisfied customers
Buick Rendezvous CXL: 02 rendezvous 3.4. Replaced bad motor
02 rendezvous 3.4. Replaced bad motor with a 4000 mile motor. Before dropping in I installed new head and intake gaskets. New plugs and wires. Engine now shows cylinder 1 and 6 constant misfired on ob… read more
Dave Nova
Dave Nova
Buick Technician
Associate Degree
1,808 satisfied customers
2000 Buick Regal: climate control..misfiring..If idling..rpms followed
My 2000 Buick Regal is accumulating electrical problems: First, the climate control started reading -12 degrees outside which shut down my air conditioning. A new control did not solve the problem, so… read more
rodcuda
rodcuda
Auto repair pro, 30 years experience
Associate Degree
74 satisfied customers
1995 buick park ave - 3800 engine. engine runs very rough
1995 buick park ave - 3800 engine. engine runs very rough at low idle and stalls. Runs ok once it is moving. Already replaced TPS, Low idle control servo and EGR valve… read more
RussMasterTech
RussMasterTech
GM Service Technician
3 Years College
546 satisfied customers
1994 BUICK CENTURY: IT WONT IDLE WELL...THROTTLE..SURGES
1994 BUICK CENTURY. I CHANGED THE PLUGS AND WIRES AND NOW IT WONT IDLE WELL. WHEN I PRESS THE THROTTLE IT SURGES AND POPS. I CHECKED THE WIRES AND ALL IS CORRECT. WHAT ARE THE SYMPTOMS OF A BAD THROTT… read more
Gm Tech (Cam)
Gm Tech (Cam)
Owner/Technician
Vocational, Technical or Trade Scho
6 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