Chevy

Chevrolet Repair Questions? Ask a Chevy Mechanic for Answers ASAP

Ask an Expert,
Get an Answer ASAP!

Chevy

2002 Yukon XL 1500: Have codes p300, P0171 and P0174..hesitation

Customer Question
I have 2002 Yukon XL...
I have 2002 Yukon XL 1500. Have codes P0300, P0171 and P0174 and have also seen P0172. At idle there is hesitation, dropping out when cold.
Submitted: 8 years ago.Category: Chevy
Show More
Show Less
Ask Your Own Chevy Question
Answered in 3 minutes by:
11/21/2009
Chevy Mechanic: John, Master A.S.E Automotive technician replied 8 years ago
John
John, Master A.S.E Automotive technician
Category: Chevy
Satisfied Customers: 9,176
Experience: A.S.E MasterTechnician A1-A8 w/L1,38 years experience General Motors Master Technician
Verified

HelloCustomer

This is a pretty common problem & I am sending info to repair your problem.

PIP3232B: Cold Engine Idle Misfire Or DTCs P0171 P0174 - keywords 4.8 5.3 6.0 air cold crack hesitate idle intermittent internal intake leak lean misfire miss P0171 P0174 P0300 power rough surge vacuum - (Feb 7, 2007)

Subject:Cold Engine Idle Misfire or DTCs P0171 P0174

Models:2002-2005 Cadillac Escalade
1999-2005 Chevrolet Avalanche, Express, Silverado, Suburban, Tahoe, Trailblazer
1999-2005 GMC Savana, Sierra, Yukon
2003-2005 Hummer H2

 


This PI was superseded to update parts information. Please discard PIP3232A.


 

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

99 through 05 GEN III truck engines may experience any of the following:

  1. A cold rough idle that diminishes as the engine warms up.
  2. Possible DTCS P0171, P0174, or P0300.
  3. Random misfires at idle.

The intake gasket seals may be leaking around the intake ports, causing a lean condition. The intake gasket seals may leak around the bottom side of the port, making it a challenge to detect the vacuum leak. The technician may also notice lower than normal MAF readings if the intake seals are leaking.

  1. If leaking intake gasket seals are found, replace the intake gaskets. During the repair be sure to use the current GMSPO part number for replacement intake gaskets. The current GMSPO part number for intake gaskets will have a teal green intake gasket seal. The old version of the intake gaskets were orange in color. Use only the teal green colored gaskets for a repair.
  2. The intake plenum should also be checked for excessive warpage that may cause an uneven clamping pressure of the seal. If the plenum is found to be warped it will need to be replaced. Service Information states, "An intake manifold with warpage in excess of 3 mm (0.118 in) over a 200 mm (7.87 in) area should be replaced". Intake warpage is measured at the gasket sealing surfaces, and should be measured within a 200 mm (7.87 in) area. This measurement is across only two of the intake runner port openings. Measurements taken across the entire distance of all four intake runner ports will lead to unnecessary manifold replacements.
Ask Your Own Chevy Question
Customer reply replied 8 years ago
Is there a procedure/instructions for replacing the intake gaskets?
Chevy Mechanic: John, Master A.S.E Automotive technician replied 8 years ago

Yes ,this should help.

Intake Manifold Replacement

    Important: The intake manifold, throttle body, fuel rail, and injectors may be removed as an assembly. If not servicing the individual components, remove the manifold as a complete assembly.

  1. Remove the throttle body. Remove the fuel injectors. Object Number: 679510  Size: SH

  2. Disconnect the following electrical connectors:
    Manifold absolute pressure (MAP) sensor (1)
    Knock sensor (2)
    Exhaust gas recirculation (EGR) valve, if equipped.
  3. Remove the knock sensor harness electrical connector from the intake manifold.
  4. Set the electrical harness aside.
    Object Number: 679527  Size: SH

  5. If equipped, remove the following EGR pipe bolts:
    Intake manifold (1)
    Cylinder head (2)
    Exhaust manifold (3)
  6. If equipped, remove the EGR pipe with valve.
  7. If equipped, remove the EGR pipe gasket from the exhaust manifold.
    Object Number: 382483  Size: SH

  8. If equipped with vacuum assisted brakes, remove the vacuum brake booster hose from the rear of the intake manifold.
    Object Number: 647793  Size: SH

  9. Remove the positive crankcase ventilation (PCV) hose with valve.
    Object Number: 260159  Size: SH

  10. Remove the MAP sensor (1) from the intake manifold.
    Object Number: 492765  Size: SH

  11. Remove the accelerator control cable bracket bolts (1).
  12. Remove the accelerator control cable bracket (2) from the intake manifold.
    Object Number: 372717  Size: SH

  13. Remove the evaporative emission (EVAP) purge solenoid vent tube by performing the following:
    14.1. Remove the EVAP tube end (2) from the solenoid (1).
    14.2. Squeeze the EVAP pipe quick connect fitting (3) retainer together.
    14.3. Remove the EVAP tube end (3) from the vapor pipe.

    Object Number: 389993  Size: SH

  14. Remove the EVAP purge solenoid bolt (2), solenoid (3), and isolator (1) from the intake manifold.
    Object Number: 642285  Size: SH

  15. Remove the intake manifold bolts.
  16. Remove the intake manifold.
    Object Number: 492770  Size: SH

  17. Remove the intake manifold gaskets (1) from the intake manifold.
  18. Discard the old intake manifold gaskets.
  19. Clean and inspect the intake manifold. If equipped with EGR, clean the gasket surfaces of the EGR pipe and the exhaust manifold.
Ask Your Own Chevy Question
Customer reply replied 8 years ago
when you replace the gaskets should you use any gasket adhesive or other compound? Is there another gasket needed for the EGR?
Chevy Mechanic: John, Master A.S.E Automotive technician replied 8 years ago
Do not use sealer these are special gaskets & the EGR gasket comes in an intake set from GM.
Ask Your Own Chevy Question
Customer reply replied 8 years ago
what are the chances that the egr valve is bad? If I accept the answer will I still be able to ask a follow up question if necessary?
Chevy Mechanic: John, Master A.S.E Automotive technician replied 8 years ago
I do not believe your EGR valve is bad,it will not set all these codes.Yes .you accept the answer & come back anytime.
John
John, Master A.S.E Automotive technician
Category: Chevy
Satisfied Customers: 9,176
Experience: A.S.E MasterTechnician A1-A8 w/L1,38 years experience General Motors Master Technician
Verified
John and 87 other Chevy Specialists are ready to help you
Ask your own question now
Customer reply replied 8 years ago
Thanks for the information, now I have to decide if I want to do it myself!
Chevy Mechanic: John, Master A.S.E Automotive technician replied 8 years ago
Ok,you have a good day.
Ask Your Own Chevy Question
Customer reply replied 7 years ago
Do you have any information on how to disconnect the fule lines from the fuel rails on the intake manifold? I removed the clips but don't know how to get the connector apart.
Chevy Mechanic: John, Master A.S.E Automotive technician replied 7 years ago

This should help you.You will need a special tool that most parts suppliers keep in stock.

Metal Collar Quick Connect Fitting Service

Tool Required

Fuel Line Disconnect Tool

Removal Procedure

  1. Relieve the fuel system pressure before servicing any fuel system connection. Remove the retainer from the quick-connect fitting.
    Object Number: 12776  Size: SH

  2. Caution: Wear safety glasses when using compressed air in order to prevent eye injury.

  3. Blow dirt out of the fitting using compressed air.
    Object Number: 12780  Size: SH

  4. Choose the correct tool from the tool set for the size of the fitting. Insert the tool into the female connector, then push inward in order to release the locking tabs.
    Object Number: 12782  Size: SH

  5. Pull the connection apart.

    Notice: If necessary, remove rust or burrs from the fuel pipes with an emery cloth. Use a radial motion with the fuel pipe end in order to prevent damage to the O-ring sealing surface. Use a clean shop towel in order to wipe off the male tube ends. Inspect all the connections for dirt and burrs. Clean or replace the components and assemblies as required.

  6. Use a clean shop towel in order to wipe off the male pipe end.
  7. Inspect both ends of the fitting for dirt and burrs. Clean or replace the components as required.

Installation Procedure


    Object Number: 12784  Size: SH

    Caution: Always apply a few drops of clean engine oil to the male pipe ends before connecting the fuel pipe fittings in order to reduce the risk of fire and personal injury. This will ensure proper reconnection and prevent a possible fuel leak. During normal operation, the O-rings located in the female connector will swell and may prevent proper reconnection if not lubricated.

  1. Apply a few drops of clean engine oil to the male pipe end.
    Object Number: 12786  Size: SH

  2. Push both sides of the fitting together in order to snap the retaining tabs into place.
    Object Number: 12787  Size: SH

  3. Once installed, pull on both sides of the fitting in order to make sure the connection is secure.
  4. Install the retainer to the quick-connect fitting.
Ask Your Own Chevy Question
Ask John Your Own Question
John
John
John, Master A.S.E Automotive technician
Category: Chevy
Satisfied Customers: 9,176
9,176 Satisfied Customers
Experience: A.S.E MasterTechnician A1-A8 w/L1,38 years experience General Motors Master Technician

John 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:

I was having a terrible problem with the wheel bearings on my 98 Chevy Cavalier and I suspect that using this website saved me plenty of time and money.

Todd LRochester NY

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

< Previous | Next >

Meet the Experts:

GM Tech (Cam)

GM Tech (Cam)

Chevy Technician

15,249 satisfied customers

GM Grand Master Technician 2007. 14 years experience.

Gary

Gary

Chevy Technician

9,196 satisfied customers

15 years GM master tech

Tim&#039;s Auto Repair

Tim's Auto Repair

mechanic

8,847 satisfied customers

Have owned a repair shop for 25 yrs.

Dave Nova

Dave Nova

Chevrolet Technician

7,092 satisfied customers

ASE Master Certification. GM World Class Certification

John

John

Master A.S.E Automotive technician

9,176 satisfied customers

A.S.E MasterTechnician A1-A8 w/L1,38 years experience General Motors Master Technician

Don - Mo Lurch

Don - Mo Lurch

Auto Mech / Electronics

2,900 satisfied customers

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

Ron Z.

Ron Z.

- Chevy Tech -

2,682 satisfied customers

18+yrs experience. State Inspector and Chevy Diagnostics

< Previous | Next >

Related Chevy Questions
Engine makes a noise like a spark knock or an exhaust leak
Engine makes a noise like a spark knock or an exhaust leak from the right side of the engine during acceleration, this doenst happen all the time but it seems to run better when it doesnt make the noi… read more
Dodge expert
Dodge expert
ASE MASTER TECH, REPAIR FACILITY OWNER
High School or GED
3,636 satisfied customers
Replaced both 02 sensor on secondary exhaust 8 coil packs
Replaced both 02 sensor on secondary exhaust 8 coil packs spark plus ,mass air flow sensor spark plug wires ,purge valve and i still have code 300 and 138 will show up every now and then runs very rou… read more
roy
roy
Associate Degree
3 satisfied customers
I need to replace exhaust manifolds on a 1970 Chevy 1/2 tin
I need to replace exhaust manifolds on a 1970 Chevy 1/2 tin stock 450 2 barrel Automatic what would be the best manifold for fuel economy… read more
camerontech
camerontech
20 year experience diagnostic technician
class a
544 satisfied customers
Where is the Exhaust Cam Position Actuator Solenoid located
Where is the Exhaust Cam Position Actuator Solenoid located on 93 GMC Serra Trunk ? … read more
Joecamel90
Joecamel90
Technician
Associate Degree
24 satisfied customers
We are having smoke out of the exhaust after idialing for
we are having white smoke out of the exhaust after idialing for awhile. … read more
Chris (aka - Moose)
Chris (aka - Moose)
Vocational, Technical or Trade Scho
108 satisfied customers
P0420 bank 1. 06 malibu maxx 3.5. Checked for exhaust leaks
Checked for exhaust leaks sprayed around intake looking for vaccume leakes … read more
Ron Z.
Ron Z.
- Chevy Tech -
Vocational, Technical or Trade Scho
2,682 satisfied customers
What's exhaust manifold gasket is better the steel one or an
What's exhaust manifold gasket is better the steel one or an aftermarket one that feels like rubber. I took my catalyic converter off my Chevy Malibu and it has two steel gaskets is that normal? 2005 … read more
Kevin
Kevin
workshop foreman /master tech/mot tester
0 satisfied customers
Exhaust smell with a/c on and windows closed. No it has been
we have mechanics at the factory they checked the exhaust mnaifold and a/c intake but could not pinpoint it we can take it to the dealer if needed … read more
Jerry Newton
Jerry Newton
Vocational, Technical or Trade Scho
2,066 satisfied customers
There is some exhaust fumes getting in the car, 1988 Chevy
Hi, there is some exhaust fumes getting in the car, 1988 Chevy Coup, need a mechanic to fix it… read more
eauto
eauto
self employed
High School or GED
74 satisfied customers
Cleaning exhaust fluid message then goes into engine power
Cleaning exhaust fluid message then goes into engine power reduced. Anything I can do we are in the boonies … read more
Eric
Eric
Retired
N/A
14,436 satisfied customers
Locked out, having problems with the knock sensors had to
having problems with the knock sensors had to erase codes to get home , now im locked out of the computer … read more
eric remington
eric remington
FORMER SHOP OWNER/TECHNICIAN/INSPECTOR
associates degree
290 satisfied customers
I have a 2008 Chevy Cheyenne 5.3 L with a knock sensor code
I have a 2008 Chevy Cheyenne 5.3 L with a knock sensor code the intake is removed and the conventional picture does not match what I have truck is made in Mexico California emission standards… read more
Don - Mo Lurch
Don - Mo Lurch
Auto Mech / Electronics
Vocational, Technical or Trade Scho
2,900 satisfied customers
Knock sensor on bank 2, catalytic converter on bank 2 codes
knock sensor on bank 2, catalytic converter on bank 2 codes on 4.3 liter 2011express van … read more
Ron Z.
Ron Z.
- Chevy Tech -
Vocational, Technical or Trade Scho
2,682 satisfied customers
I put new exhaust manifolds and split the exhaust on my 94
I put new exhaust manifolds and split the exhaust on my 94 454. The manifolds had a place for the o2 sensor so I put it there. Previously it was just behind the crossover pipe in the exhaust. Will the… read more
Eric
Eric
Retired
N/A
14,436 satisfied customers
2002 tahoe 5.3, no 5V dc at the knock sensor plug in [pin 11
2002 tahoe 5.3, no 5V dc at the knock sensor plug in [pin 11 and 51] wires OK to PCM, with key on...where does the 5V originate from? any out side source or fused, switched before entering PCM? … read more
Jaybird61
Jaybird61
Master Automotive Mechanic
1,888 satisfied customers
On a 2003 Chevy 3.8 engine, can any exhaust gasses get in
On a 2003 Chevy Monte Carlo 3.8 engine, can any exhaust gasses get in the radiator other that a cracked head or bad head gasket? No oil in the coolant, it does not idle rough, no white exhaust from st… read more
David Craig
David Craig
OWNER/MECHANIC
Associates
3,927 satisfied customers
The engine knock sensor in front of engine. is there suppose
the engine knock sensor in front of engine. is there suppose to be a wire to connect it? I replaced the sensor and the engine light is still on. its a 2005 impala … read more
Gunvir Singh
Gunvir Singh
1,702 satisfied customers
Will a bad knock sensor cause the cam sensor to act up on a
Will a bad knock sensor cause the cam sensor to act up on a '97 chevy 5.7 … read more
David Craig
David Craig
OWNER/MECHANIC
Associates
3,927 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