Car

Ask a Mechanic Online and Get Answers to Your Car Questions

Ask an Expert,
Get an Answer ASAP!

Car

Isuzu Trooper LS: 96 isuzu trooper miss fire #4 replaced plugs

Customer Question
96 isuzu trooper miss fire...
96 isuzu trooper miss fire #4 replaced plugs copper plus switched injectors switched col packs replaced crank sensor cam sensor plenum gasket intake gasket checked spark,plug is very black but not very warm, checked camshaft for bad lobe 155 psi compression all cylinders what am i missing?
Submitted: 5 years ago.Category: Car
Show More
Show Less
Ask Your Own Car Question
Answered in 7 hours by:
7/31/2012
Auto Mechanic: The Audi Doctor, Technician replied 5 years ago
The Audi Doctor
The Audi Doctor, Technician
Category: Car
Satisfied Customers: 2,429
Experience: Over 30 years experience, 17 years with Audi, Factory trained
Verified
Hello,

Thank You for choosing Just Answer for your query. Yes, I can help you.

A) There is a misfire Technical Service Bulletin #99-020 dated June 7 1999 regarding a re-flash on the ECM.

B) These vehicles are also very sensitive to the spark plug selection. I recommend ONLY NGK PFR5G-11.

C) These injectors are prone to bleeding down and leaking fuel into the cylinders causing misfires, mainly when cold.

D) Also the fuel pressure regulator fails and leaks fuel into the vacuum line.

E) Corrosion under the coil can cause a poor ground and the coil can cause a misfire.

All common causes of misfire issues on this year model. That said, I do not think they are going to cure the misfire, but they should be checked/eliminated.

I am going to assume that this vehicle has a direct misfire in #4 cyl. that is always present. Please let me know if that is not the case, as you did not indicate this on your question, only the fact that P0304 is stored, and the plug is black. Is the spark plug back and wet, or black and dry?

Based on the fact that the spark plug is black indicates that there is fuel present, but it is not being ignited. If you have carried out all the steps listed properly I suspect the Ignition Control Module is failed.

First I suggest you inspect the wires/terminals at the ignition module, and coil. Also check for corrosion under the coil. You could also “pin out” and test the wires from, the Ignition module to the coil, or simply replace the Ignition module.
graphic

Let me know if you have any further comments or questions.

I hope I have answered your questions and addressed your concerns. Should you have further questions on this matter, please do not hesitate to ask. I want you to be 100% satisfied with my answer.

Positive feedback, referrals and bonuses are always APPRECIATED.

Thank You!
Jake “The Auto Doctor”
Ask Your Own Car Question
Customer reply replied 5 years ago
i have pined out the wires going to the coil and placed coil on a ground and checked plug spark (ok) also swapped coil 2 and 4 problem stayed at 4 and replaced the (ecm)
with a used one,fuel pressure is ok. hooked up code reader and the p0304 is always their. the plug is black and dry i have swapped injectors from 2 and 4 and the problem stayed at #4
Auto Mechanic: The Audi Doctor, Technician replied 5 years ago
How about the "ignition" control module? Not the "engine" control module.

Also, just for curiosity you could swap the injector wires with the adjacent cylinder as they are not sequential.

Thanks Jake
Ask Your Own Car Question
Customer reply replied 5 years ago
where is the icm located? I dont think the wires from #2 will reach #4 and wouldn't that change the fuel timing? In any way would the o2 sensors be to blame i know i have a bad one their are 4 of them and they were all unplugged when i bought the car i think their plugged in the correct i spot pinned out all wires and traced them back according to a diagram provided by one of you 6 months ago. originally it all started as sluggish and low power on the bottom end but if you put it to the floor it would go sluggish then all of a sudden pick up and put you in you're seat.
Auto Mechanic: The Audi Doctor, Technician replied 5 years ago
This is not a "sequential" system (no fuel timing).


This is where the module is located. I sent you a close up earlier.

I don't know what has happened in the past. I am only addressing your "misfire" question.

Not being able to experience the condition first hand put’s me at a significant disadvantage. If you can better/best describe the condition, as well as anything else that has been done to try and correct the issue. Also a time line of the events that led to the condition would be quite helpful.

The quality of my answer is based directly on the quality of your question and description. So please include anything else that may help me to better understand the condition and how it all came about.

Thank you!
Jake
Ask Your Own Car Question
Customer reply replied 5 years ago
bought car
replaced tranny (5 speed)
drove would run ok on top if you got in it
pin tested o2 sensors
changed the way i had them plugged in
now constant misfire p0304 p0300
checked compression (155lbs)
replaced gaskets cleaned intake runners checked cam lobes valve lash hot and cold
replaced cam sensor
replaced crank sensor
replaced plugs
swapped coils
swapped injectors
rechecked o2 sensor wiring looks correct to diagram
replaced ecm
checked plug (black and dry)
contacted you
Auto Mechanic: The Audi Doctor, Technician replied 5 years ago
OK, you check for spark in #4 cylinder and then you compare it to an other cylinder, how do they compare? What kind distance gap will the spark jump on both cylinders, and is it sparking as often? If #4 is weaker than the other I would replace the Ignition control module.

Thanks Jake
Ask Your Own Car Question
Customer reply replied 5 years ago
the spark is the same the gap is .035 and it sparks just as often i have timed it with a light on #2 and #4 the spark will jump off the plug about 1 to 1.5 inch on both 2 and 4
Auto Mechanic: The Audi Doctor, Technician replied 5 years ago
OK, I think that about covers it. I would swap the injector wire connectors if they do not reach make up some extensions. If the misfire is still in #4 there is a problem in the head possibly a broken valve spring(?).

Do you have a cylinder leakage tester? It wouldn't necessarily show a broken valve spring, but could provide a clue.

Also, put a vacuum gauge on the intake manifold. Is it steady at idle?

What happens to the vacuum reading when you drive?

Is it a dead miss all the time(idle/cruise/accelerating)

Thanks Jake
Ask Your Own Car Question
Ask The Audi Doctor Your Own Question
The Audi Doctor
The Audi Doctor
The Audi Doctor, Technician
Category: Car
Satisfied Customers: 2,429
2,429 Satisfied Customers
Experience: Over 30 years experience, 17 years with Audi, Factory trained

The Audi Doctor 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 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

Lurch. Thank you very much. I had real doubts about this website but your promptness of response, quick followup and to the point answer with picture was incredible.

CharlesWalnut Creek, CA

As a single woman, I really appreciate an excellent and affordable opinion.
Thank you Geordie, I will not hesitate to contact justanswer in the future!

SueCharleston, WV

Another great insight to what may be the problem. I will have my mechanic take a look at it tomorrow. Thanks again, Frank...you do indeed know your stuff.

JimCastleberry, FL

The nearest Volvo dealer is 160 miles away. Best $15 bucks I have spent in a long time!

Paul MCorpus Christi, TX

< Previous | Next >

Meet the Experts:

Chris (aka-Moose)

Chris (aka-Moose)

Technician

1,243 satisfied customers

16 years of experience

Ted G.

Ted G.

ASE Certified Technician

1,724 satisfied customers

20 years auto repair experience, ASE Master Tech, Mechanical Failure consultant, Expert Witness

George H.

George H.

ASE Certified Technician

1,537 satisfied customers

ASE Master Tech 15+ yrs, AAS Automotive Technology, Factory trained Asian specialist

GM Tech (Cam)

GM Tech (Cam)

Auto Service Tech

669 satisfied customers

GM Grand Master Technician 2007. 14 years experience.

Amedee

Amedee

Former ASE Master Tech

2,520 satisfied customers

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

Jerry

Jerry

Master Mechanic

2,181 satisfied customers

ASE master, 30+ years. All makes and models. Trouble shooter, shop forman, service manager

Richard

Richard

ASE Certified Technician

1,000 satisfied customers

12 years Ford Lincoln/Mercury Jaguar dealership as a technician and shop foreman reparing all makes

< Previous | Next >

Related Car Questions
The wipers have slowed down. And yes. 1996 regular cherokee.
yes I am and I have tried checking for corroded connections … read more
Edward Clayton
Edward Clayton
Associate Degree
1,033 satisfied customers
I have recently changed my ccv valve & maf sensor on my 2003
I have recently changed my ccv valve & maf sensor on my 2003 BMW 316ti. Since then the vehicle will not run. It is idling rough for a short period and cuts out. I have EML and auto transmission warnin… read more
sprinkles08
sprinkles08
Technician
High School or GED
11 satisfied customers
Over heats after a couple hard pulls, new radiator and
Over heats after a couple hard pulls, new radiator and thermostat. No leaks … read more
indy-tech
indy-tech
Shop owner, technician
Vocational, Technical or Trade Scho
11 satisfied customers
I can't seem to get voltage to my Ignition Coil, but my ASD
I can't seem to get voltage to my Ignition Coil, but my ASD Relay and Fuse are fine as far as I can tell. I have 12 volts at both, but nothing at the connector to the Ignition coil. As well, I have co… read more
Edward Clayton
Edward Clayton
Associate Degree
1,033 satisfied customers
After driving a few minutes in DRIVE transmission slips to
After driving a few minutes in DRIVE transmission slips to lower gear … read more
Stephen, MBA
Stephen, MBA
Master's Degree
166 satisfied customers
I have a 97 Jeep 4cyl auto, a/c. Besides going to a 350V8
I have a 97 Jeep 4cyl auto, a/c. Besides going to a 350V8 swap, what could I do to improve hp and low end torque? … read more
BOBBYSS
BOBBYSS
TECHNICIAN/ADVISOR
Associate Degree
8,343 satisfied customers
2014 Subaru Forester. Had 2 amateur radios plugged into rear
2014 Subaru Forester. Had 2 amateur radios plugged into rear accessory power outlet. Keyed up one of them and both shut down, no power. Which fuse and where is it located? … read more
Stephen, MBA
Stephen, MBA
Master's Degree
166 satisfied customers
I set the child proof lock to the on position on my 2006
I set the child proof lock to the on position on my 2006 passat (rear passenger side) now I can't open the door! … read more
Eurocar Inc
Eurocar Inc
Master Audi/VW Tech
Associate Degree
1,773 satisfied customers
I've worked with Ted Ritter, Genchi Genbutsu & Skyvisions
Hello,I've worked with Ted Ritter, Genchi Genbutsu & Skyvisions before. But any technician can probably help me if they're not readily available too.02 Toyota Sequoia 4WD, 183K milesI seem to have res… read more
Pete
Pete
Mechanic
Construction, Plant Fitter
61 satisfied customers
Can I replace the thrust bearing on a 2005 pt cruiser that
Can I replace the thrust bearing on a 2005 pt cruiser that has only ahalf flange thrust bearing with a new full flange thrust bearing… read more
eurotec
eurotec
Vice President / Manager
Associate Degree
11 satisfied customers
My transmission went out. And the mechanic wants to fix
My transmission went out. And the mechanic wants to fix drive train too. I've heard they don't typically need repaired at the same time. Do I need to get a drive train? … read more
Edward Clayton
Edward Clayton
Associate Degree
1,033 satisfied customers
Drove fine yesterday and today the doors would not unlock
drove fine yesterday and today the doors would not unlock using the button on key. opened doors with actual key and car will not start. no power in any way. … read more
sprinkles08
sprinkles08
Technician
High School or GED
11 satisfied customers
Car coolant temp fluctuates between low and normal. Just
car coolant temp fluctuates between low and normal … read more
tim37857
tim37857
Mechanic
High School or GED
71 satisfied customers
Airbag light on since bought car goes out when above 50
airbag light on since bought car goes out when above 50 degree's … read more
Eric
Eric
Auto Technician
589 satisfied customers
2005 range rover hse no heat left side. 2006 range rover
I had an diagnostic done defective motor, estimated repair 2600 dollars… read more
Pete
Pete
Independent Auto Technician
Vocational, Technical or Trade Scho
138 satisfied customers
My signals my dashboard for the heat control and radio and
My signals my dashboard for the heat control and radio and my brake ABS lights are on don't know what the problem is … read more
Stephen, MBA
Stephen, MBA
Master's Degree
166 satisfied customers
My jeep will not just turns over Ithink ithas no spark. 1994
my jeep will not just turns over Ithink ithas no spark … read more
Edward Clayton
Edward Clayton
Associate Degree
1,033 satisfied customers
The ABS and 4WD is on on my vehicle. The right rear abs
Good day, the ABS and 4WD is on on my vehicle. The right rear abs sensor was placed on same and the light came back on. … read more
Kevin
Kevin
workshop foreman /master tech/mot tester
0 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