Chevy

Chevrolet Repair Questions? Ask a Chevy Mechanic for Answers ASAP

Ask an Expert,
Get an Answer ASAP!

Chevy

Chevrolet trailblazer LT I have a cylinder 6 misfire on a

Customer Question
I have a cylinder 6...
I have a cylinder 6 misfire on a 03 Chevy trailblazer . I have changed all 6 coils spark plugs and # XXXXX injector check engine light still on . Computer was reset and came back on what do I go ?
Submitted: 6 years ago.Category: Chevy
Show More
Show Less
Ask Your Own Chevy Question
Answered in 3 minutes by:
1/26/2011
Chevy Mechanic: Ken, ASE Certified Technician replied 6 years ago
Ken
Ken, ASE Certified Technician
Category: Chevy
Satisfied Customers: 754
Experience: GM Certified Technician, 25 Years Automotive Experience
Verified
Now you need to do a cylinder leak down test to see if you have a valve problem. This motor is known for valve seat problems. Most of the time it is a miss fire at idle only at first, if driven on too long it becomes a miss fire all the time. Ken
Ask Your Own Chevy Question
Customer reply replied 6 years ago
Had diagnostic from dealer compression is good in # XXXXX and 6 did node test no open or shorts found
Chevy Mechanic: Ken, ASE Certified Technician replied 6 years ago
#)

Subject:P0300 DTC and Engine Misfire at Idle - Possible Leaking Intake Valves

Models:2004 - 2006 Buick Rainier
2002 - 2006 Chevrolet Trail Blazer
2002 - 2006 GMC Envoy
2002 - 2004 Oldsmobile Bravada
2005 - 2006 Saab 97x
with 4.2L Engine (VIN S - RPO LL8)

 



Condition/Concern:

On rare occasions, a SES light and P0300 DTC may be encountered as a result of single cylinder misfires only at idle. These misfires may or may not be felt and they will disappear off of idle. If the engine misfires do not occur at idle, this PI does not apply.

Recommendation/Instructions:

If the SI diagnostics do not isolate a cause for this concern, perform a cylinder leakage test as outlined in the "Cylinder Leakage Test" procedure in SI and document all leakage rates on the repair order. When performing the cylinder leakage test, it is very important to hold the crankshaft with the related piston at top dead center to ensure that the valves are fully closed or inaccurate results may be obtained. If an aftermarket leakdown tester is used, the instructions of the aftermarket tester should also be referenced because with some aftermarket testers, it may be necessary to limit the air pressure to 50 PSI in order to obtain accurate test results.

If a leaking intake valve is found, replace the cylinder head and valves.

Ask Your Own Chevy Question
Chevy Mechanic: Ken, ASE Certified Technician replied 6 years ago
If the miss fire is only at idle you will only find it with a leak down test. Compression test will pass. Ken
Ask Your Own Chevy Question
Customer reply replied 6 years ago
It's not a misfire during idle
Chevy Mechanic: Ken, ASE Certified Technician replied 6 years ago
when do you feel it then?
Ask Your Own Chevy Question
Customer reply replied 6 years ago
Sluggish going pass 40mph check engine light starts to flash when above 50 it 60 mph
Chevy Mechanic: Ken, ASE Certified Technician replied 6 years ago
Its only #6 what fault code is setting?
Ask Your Own Chevy Question
Customer reply replied 6 years ago
P306
Chevy Mechanic: Ken, ASE Certified Technician replied 6 years ago

does it just lack power or do you feel a bucking miss fire

 

Ask Your Own Chevy Question
Customer reply replied 6 years ago
Lacks power . Stepping on gas pedal harder to gain speed hills are worse
Chevy Mechanic: Ken, ASE Certified Technician replied 6 years ago
Do a back pressure test on the cat. If the cat is partly plugged it will cause a lack of power and can pick on one cylinder. Check the fuel pressure. Low fuel pressure can cause problems and #6 is the last one on that fuel rail. that is what i would check next. Ken
Ask Your Own Chevy Question
Customer reply replied 6 years ago
Could a fuel filter cause low fuel pressure ? Or is that just from fuel pump ?
Chevy Mechanic: Ken, ASE Certified Technician replied 6 years ago
Yes !! It acts just like a bad fuel pump or a plugged cat !! All 3 feel the same when driving down the road. Ken
Ask Your Own Chevy Question
Customer reply replied 6 years ago
So a cloged fuel filter can cause a #6 misfire ?
Chevy Mechanic: Ken, ASE Certified Technician replied 6 years ago
Yes, on that motor more than others because #6 is the last on on the fuel rail. This would cause a lean miss fire and most likely under a load when more fuel is needed. If you can see the mis fire counter on a scan tool. you will see a lot on miss fire on #6 and some on others. #6 is missing the most. Ken
Ask Your Own Chevy Question
Ask Ken Your Own Question
Ken
Ken
Ken, ASE Certified Technician
Category: Chevy
Satisfied Customers: 754
754 Satisfied Customers
Experience: GM Certified Technician, 25 Years Automotive Experience

Ken 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

4,071 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
Misfire in cylinder #1 replaced coil and spark plugs, engine
misfire in cylinder #1 replaced coil and spark plugs, engine light on and flashing. Put in injector cleaner also. … read more
eauto
eauto
self employed
High School or GED
74 satisfied customers
Crank ok but won't start when hot, fuel 55psi,spark plug
when it cold start up no problem,i even replace coolant temp sensor… read more
Michael Solis
Michael Solis
238 satisfied customers
1 cylinder Spark Plugs crack and misfire. Random at first
1 cylinder Spark Plugs crack and misfire JA: How many miles are on the car? Is it a steady misfire? Or random? Customer: Random at first 79000 mjiles JA: What is the model/year of your Chevy? Customer… read more
Pete
Pete
Independent Auto Technician
Vocational, Technical or Trade Scho
138 satisfied customers
Crank, no start. fuel pump is working. spark plugs (I think)
crank, no start. fuel pump is working. spark plugs (I think) are firing. … read more
eric remington
eric remington
FORMER SHOP OWNER/TECHNICIAN/INSPECTOR
associates degree
290 satisfied customers
I'm trying to change the spark-plugs on my 2006 chevy
Hi,I'm trying to change the spark-plugs on my 2006 chevy Malibu,3.5 But I ran into a problem,a couple of the spark-plugs seem to be froze.they don't turn one bit.how can I get them out with out Breaki… read more
Eric
Eric
Auto Technician
589 satisfied customers
Second opinion] I'm trying to change the spark-plugs on my
Second opinion] Hi,I'm trying to change the spark-plugs on my 2006 chevy Malibu,3.5 But I ran into a problem,a couple of the spark-plugs seem to be froze.they don't turn one bit.how can I get them out… read more
Jerry Newton
Jerry Newton
Vocational, Technical or Trade Scho
2,066 satisfied customers
P0300 and P0480, 09 Chevy cobalt, Coil pack, spark plugs,
P0300 and P0480 JA: What is the model/year of your Chevy? Customer: 09 Chevy cobalt JA: Are you fixing your Cobalt yourself? What have you tried so far? Customer: Coil pack, spark plugs JA: How many m… read more
roy
roy
Associate Degree
3 satisfied customers
Changed spark plugs wires coil on 2002 chevy s10 4.3 v6. no
changed spark plugs wires coil on 2002 chevy s10 4.3 v6 . no spark to engine ? … read more
kalamykid
kalamykid
Pactor automotive
Vocational, Technical or Trade Scho
97 satisfied customers
Hard starting. 1996 S10 4.3 vortec. New spark plugs, wires,
Yes.... New spark plugs, wires, distributor cap and rotor … read more
heavy_chevy_396
heavy_chevy_396
Vocational, Technical or Trade Scho
2,518 satisfied customers
Want to replace spark plugs 2012 chevy Malibu 2.4 ltr but
Want to replace spark plugs 2012 chevy Malibu 2.4 ltr but plastic cover over entire engine bay has me concerned how do I remove this cover to access plugs? … read more
Ron Z.
Ron Z.
- Chevy Tech -
Vocational, Technical or Trade Scho
2,682 satisfied customers
Misfire at idle changed egr valve and tube spark plugs and
Misfire at idle changed egr valve and tube spark plugs and wires got a p0455 code … read more
Dan
Dan
Automotive Technician
Vocational, Technical or Trade Scho
25 satisfied customers
No spark to my spark plugs, its a 1986, not sure exactly how
its a 1986, not sure exactly how many miles .... there is no spark to the plugs … read more
Jaybird61
Jaybird61
Master Automotive Mechanic
1,879 satisfied customers
The check engine is on. I have changed all the spark plugs
Hi the check engine is on. I have changed all the spark plugs and core and ignition core. … read more
GM Tech (Cam)
GM Tech (Cam)
Chevy Technician
Vocational, Technical or Trade Scho
15,249 satisfied customers
Just had my car at the shop for spark plugs and new wires.
Just had my car at the shop for spark plugs and new wires. Now all my sensors are going crazy. Why is this happening? 2004 Chevy Malibu … read more
Chris (aka - Moose)
Chris (aka - Moose)
Vocational, Technical or Trade Scho
108 satisfied customers
2009 spark plugs wet engine run rough loss of power. 41k
2009 spark plugs wet engine run rough loss of power. … read more
GM Bob
GM Bob
Automobile Technician
High School or GED
986 satisfied customers
Any ideas how to get the #3 spark plug out without taking
any ideas how to get the #3 spark plug out without taking the engine apart is there a special tool you can buy… read more
Gary
Gary
Chevy Technician
Vocational, Technical or Trade Scho
9,196 satisfied customers
I change the spark plugs and the wiring plugs but I got a
I change the spark plugs and the wiring plugs but I got a misfire now I dont what to do … read more
fordguy4u
fordguy4u
Automotive Tech
Vocational, Technical or Trade Scho
70 satisfied customers
Check engine light after spark plug replacment, Stays on,
Check engine light after spark plug replacment JA: Does the light stay on, or does it blink? Customer: Stays on JA: What is the model/year of your Chevy? Customer: 2010 Chevy cobalt 8500 miles JA: Are… read more
AMEDEE
AMEDEE
AUTOMOTIVE TECHNICIAN
Vocational, Technical or Trade Scho
9,105 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