GM

GM repair problems? Ask a GM repair expert now.

Ask an Expert,
Get an Answer ASAP!

GM: I have 1995 Yukon 4x4 with a 350 cui engine. Throttle…

Customer Question
I have 1995 Yukon 4x4...
I have 1995 Yukon 4x4 with a 350 cui engine. Throttle body fuel supply. Had the engine & transmission rebuilt at 290 K miles (8 months ago). Then my normal mechanic who did the work got gravely ill. Over time i developed a miss that continued to progress. At idle I can unplug the plug wire on #3 cylinder and it has no impact on engine performance.
Have had it tuned up by a "professional" (new plugs wires and compression check was OK) same miss.
Took things into my own hands and checked compression (good). Then the settings of the valves on that cylinder. Intake valve setting was a bit loose and adjusted. Re checked compression (good). Rechecked timing which I put at 2-3 degrees Above TDC. Mechanic had it at 5. Runs better but still has a little miss. I can still unplug that #3 wire at idle and it does not affect engine. Your thoughts?
Submitted: 3 years ago.Category: GM
Show More
Show Less
Ask Your Own GM Question
Answered in 17 minutes by:
6/13/2015
GM Mechanic: Gary, GMC Technician replied 3 years ago
Gary
Gary, GMC Technician
Category: GM
Satisfied Customers: 18,031
Experience: 15 years gm master tech/15 years ASE master tech
Verified
all other 7 cylinders effect the idle when unplugged ?compression was good from you are saying is there visual spark from the # ***** plug wire to the plug ?
Ask Your Own GM Question
GM Mechanic: Gary, GMC Technician replied 3 years ago
just to be sure this has throttle body injection with 2 big injectors on top of the throttle body ?
Ask Your Own GM Question
Customer reply replied 3 years ago

Correct. Very puzzling situation!

GM Mechanic: Gary, GMC Technician replied 3 years ago
at this point with just # ***** cylinder doing this and the compression is good and there are NO vacuum leaks the issue has to be an internal issue inside the distributor firing # ***** cylinder at the wrong timepick up a reman distributor from Napa or Pep Boys and swap it outthere really is not much more it can be as if it was a fuel injector issue it would effect that whole bank and the compression is good
Ask Your Own GM Question
Customer reply replied 3 years ago

OK Thanks. Was hoping to avoid major work. The backup mechanic who tuned it up did not impress me a bit!!! He wanted to start taking the heads off of the motor to look around.

I'll look down that avenue and see what is required to make that swap.

GM Mechanic: Gary, GMC Technician replied 3 years ago
since the compression is good i am assuming the valves are opening and closing the same distance visually as the others on that bank when cranking it overthe only outside weird thing to cause this would be a sticking valve guide sticking a # ***** valve or the cam worn but you would usually pick up the sticking guide during the compression testyou could do a running compression test with the tire core removed from the compression gauge hose and see with the engine running what it reads then try # ***** and see if it reads the sameif it does at idle you could connect a vacuum gauge to manifold vacuum and see at idle when its skipping if the vacuum gauge needle bounces at idle if it does then usually that a valve issuebut at this point its a valve train issue or distributor issue
Ask Your Own GM Question
Customer reply replied 3 years ago

I have been tied up for the last week but replaced the distributor as you suggested. I was able to easily set the timing but still have essentially the same issue with the #3 cylinder not seeming to be doing anything at low rpm's. the plugs were placed on the entire engine bu a mechanic and I replaced the one on #3 cylinder a while back. I'm going to swap plugs in #1 and 3 cylinders just to see if anything changes.

GM Mechanic: Gary, GMC Technician replied 3 years ago
ok let me know
Ask Your Own GM Question
Was this answer helpful?

How JustAnswer works

step-image
Describe your issueThe assistant will guide you
step-image
Chat 1:1 with a gm mechanicLicensed Experts are available 24/7
step-image
100% satisfaction guaranteeGet all the answers you need
Ask Gary Your Own Question
Gary
Gary
Gary, GMC Technician
Category: GM
Satisfied Customers: 18,031
18,031 Satisfied Customers
Experience: 15 years gm master tech/15 years ASE master tech

Gary 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)

GMC Mechanic

5,844 satisfied customers

GM Grand Master Technician 2007. 14 years experience.

Gary

Gary

GMC Technician

18,031 satisfied customers

15 years gm master tech/15 years ASE master tech

car tech

car tech

ASE Certified Technician

449 satisfied customers

25 year master tech and shop owner

Chris (aka- Moose)

Chris (aka- Moose)

GMC Technician

234 satisfied customers

16 years of experience

Paul M ASE Master

Paul M ASE Master

ASE Master Tech

187 satisfied customers

ASE Master Tech 20+ Years

Anthony

Anthony

GMC Technician

489 satisfied customers

GM Certified

Amedee

Amedee

GMC Technician

470 satisfied customers

ASE certified tech with advanced level specialist. Wisconsin certified emissions state inspector

< Previous | Next >

Related GM Questions
2004 gmc yukon xl p0300 #5 and #4 cyds miss firing at lidle
2004 gmc yukon xl p0300 #5 and #4 cyds miss firing at lidle but stop when rpms are above 1000… read more
Jared D
Jared D
Shop Supervisor
Bachelor\u0027s
3 satisfied customers
GM Yukon: I have a 2007 GMC Yukon that has a check engine light
I have a 2007 GMC Yukon that has a check engine light coming on and service stabiltrack light coming on. The code for the check engine light is P0301, I have replaced plug wires and plugs, looking on … read more
Gary
Gary
GMC Technician
Vocational, Technical or Trade Scho
18,031 satisfied customers
GM Buick Century: I have a 92 buick century wagon with the
I have a 92 buick century wagon with the 3.3l engine. It started running rough at idle and while driving, it shakes/vibrates rough when holding a steady speed on level highway. I changed the spark plu… read more
Gary
Gary
GMC Technician
Vocational, Technical or Trade Scho
18,031 satisfied customers
GM suburban: i have 99 gmc suburban k1500 and my wife overheated
i have 99 gmc suburban k1500 and my wife overheated and cracked both heads i just put in two new heads on the truck. i forgot to set the truck to top dead center before i pulled the distributor. pulle… read more
Gary
Gary
GMC Technician
Vocational, Technical or Trade Scho
18,031 satisfied customers
GM h2: I have a hummer h2 with a 6l with a clylinder miss according
I have a hummer h2 with a 6l with a clylinder miss according to miss counter and changed coil and plugs and wires swapped injectors checked compression and its at 140 psi on #6 cylinder don't see any … read more
Gary
Gary
GMC Technician
Vocational, Technical or Trade Scho
18,031 satisfied customers
GM Yukon XL: My Yukon is knocking and shaking. The vehicle
My Yukon is knocking and shaking. The vehicle has been parked for several months while I acquired the funds to change the trans. That is done. the day before I parked it the weather was really cold th… read more
Eric
Eric
Retired
N/A
14,436 satisfied customers
GM yukon: Hay guy I finaly found the the timeing line up for
Hay guy I finaly found the the timeing line up for the harmonic balancer after one of you guys told me about removing the raditor shield that made it easy to find, do now i have TDC for my GM Yukon 5.… read more
kwiggins29059
kwiggins29059
Associate Degree
219 satisfied customers
2004 GMC Sierra 1500: Miss..it misfire a ton on the machine..Mileage
2004 GMC Sierra 5.3 liter regular gas (not felx) I have a Dead Miss in #4 on my 2004 GMC Sierra 1500 5.3 engine. I have watched it misfire a ton on the machine. Mileage 109,000. Scanner Code 0200 Inje… read more
Ivan
Ivan
Automotive Instructor
Vocational, Technical or Trade Scho
3,337 satisfied customers
2002 gmc yukon: misfires between a sparkplug coil or valvetrain origin
how can you tell the difference in misfires between a sparkplug coil or valvetrain origin - 2002 gmc yukon xl - 5.3 z engine… read more
Hal
Hal
owner/service tech
Vocational, Technical or Trade Scho
848 satisfied customers
99 yukon slt: replaced a timing belt spark plugs and wires..rear end
hello I have a 99 yukon slt I have replaced a timing belt spark plugs and wires and it still will not start. oh yeah I had to replace the rear end b/c it caught on fire.I'm wondering if you can point … read more
john
john
MASTER AUTOMOTIVE TECHNICIAN
2 YEARS COLLEGE
10 satisfied customers
1996 gmc: Idle and a miss when I drive down the road..distributor cap
I have a 1996 gmc van. It has a miss at Idle and a miss when I drive down the road. I replaced the plugs, wires and distributor cap. This did not fix the problem. I had the local mechanic put the Snap… read more
Pete
Pete
Independent Auto Technician
Vocational, Technical or Trade Scho
138 satisfied customers
1996 gmc yukon: cranking..tdc..tooth on the timing gears
i have a 1996 gmc yukon. it died. i checked the timing and it seemed to be trying to fire, while cranking, at tdc. i thought it might have slipped a tooth on the timing gears. so i moved the distribut… read more
Steve
Steve
Chevrolet Service Technician
Vocational, Technical or Trade Scho
82 satisfied customers
1995 gmc: throttle body..intek gaskets there no leaks..injector
i have a 1995 gmc sierra extended cab 4x4, 350 tbi engine, it has what it seems to be a miss at idle, but have changed plugs, wires, distributor cap, rotor button, oxygen sensor, rebuilt the throttle … read more
Ironmike
Ironmike
ASE Master L1 performance ,Ford tech
Vocational, Technical or Trade Scho
1,773 satisfied customers
94 GMC: Vin..distributor..it mater where the rotor lands when inserted
94 GMC Jimmy Vin w 4.3 v6 Removed distributor. does it mater where the rotor lands when inserted into the motor? or do i just put the number one plug wherever it lands when inserted?… read more
Jettadan1
Jettadan1
Lead mech
Some college
1,421 satisfied customers
envoy: miss on #5 cylinder..replaced coil and plug..injector pulse
I have an 04 envoy 4.2 engine with a miss on #5 cylinder. have replaced coil and plug,checked fuel pressure, checked injector pulse with noid light. checked compression running and static. have remove… read more
Ironmike
Ironmike
ASE Master L1 performance ,Ford tech
Vocational, Technical or Trade Scho
1,773 satisfied customers
2000 gmc: cylinders..throttle body, and have swapped the coil pack
My 2000 GMC Seirra C-1500 with 5.3L engine is tripping a code 0300, random multiple misfires. When I checked the data with a Mac Mentor, I found that cyl 1 & 6 are the cylinders are misfiring. I have … read more
Joel
Joel
GM Journeyman technician
Associate Degree
1,230 satisfied customers
2003 gmc: 5.3 it has a miss-fire in cylinder 4 an 5..rpm..goes away
i have a 2003 gmc 5.3 it has a miss-fire in cylinder 4 an 5 when car idles under 700 rpm. above miss goes away. new injector were done, new coils and wires, new intake manifold. grounds to the block w… read more
GM Tech (Cam)
GM Tech (Cam)
GMC Mechanic
Vocational, Technical or Trade Scho
5,844 satisfied customers
96 yukon: code P0305 we replece wires cap rotor spark an coil
I have 96 yukon 5.7 de pc phash get code P0305 we replece wires cap rotor spark an coil an still de code dear… read more
goodwrench9124
goodwrench9124
Lead Tech/ Shop Leader
Vocational, Technical or Trade Scho
2,571 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