How JustAnswer Works:

  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.

Ask Geordie Your Own Question

Geordie, Mobile Mechanic & Motor Trader
Category: Car
Satisfied Customers: 456
Experience:  22 years of mechanical experience, and I am the mechanic in my own automotive partnership
Type Your Car Question Here...
Geordie is online now
A new question is answered every 9 seconds

2001 isuzu rodeo: Random catalytic converter..coil packs

Customer Question

2001 isuzu rodeo - Random misfire. I have had a misfire in my engine for a long time. I had to replace my catalytic converter once bucause of it once, but when I unplug my coil packs they all seem to work.
Submitted: 7 years ago.
Category: Car
Expert:  Geordie replied 7 years ago.


Random misfires are usually caused by intake system air leaks, and you say that the vacuum is low, which would point to an intake air leak.

Have a good check of all the intake hosing and vacuum lines. If you spray carb spray or the like around all the seams and joins and the engine revs increase slightly, then you have found a leak.

Let me know how you get on and we'll trake it from there.

Very best regards


Customer: replied 7 years ago.
Sorry I waited for too long to get a reply. While I was waiting I researched the net for answers and found a lot of information. I will be checking into many of these posts that I have read. I tried your suggestion once before with no results but may try it again. It is a nice and easy troubleshooting technique. I thank you for your time and attention to this matter.
   Here is a little something for your troubles. It is the most comprehensive breakdown for troubleshooting these errors that I have found. Keep it under your belt and maybe you can ase it in the future. and if all this fails I will give you another chance.

1) Take off and inspect every vaccume line going to the manifold. This
should not take too much time and is FREE. Usually the smaller diameter
lines are your problem because they split eaisley. I had a split one
going to the FPR.

2) Remove your EGR Valve and inspect and clean. Make sure it is not
stuck open. If your EGR Valve is stuck open then it is putting Exhaust
Gas in the intake during idle which will kill the engine. Again this is super
easy. Maybe some PB Blaster on the two bolts if they are stuck. Before
you put the EGR back on check that you have vacume on the intake port.
There are two holes under the EGR valve. One for exhaust one for intake.
Plug the exaust hole (warning hot), and plug the intake. Start the truck
and make sure the intake has vacume by removing the plug. Should
make a loud sucking noise and motor might die so be quick.

3) PCV valve. If stuck open this will kill your engine at idle and give you
bank 1 and 2 lean. Just replace it with an ISUZU PCV vlave. You can
get these at a HONDA dealer. Just ask for one for a 00' PASSPORT.

4) For the ION sensing ignition use only Denso PK16PR11 spark plugs.

5) Fuel filter. #1 problem when your truck stumbles when you first start
it. After it gets really clogged your truck dies.

6) Fuel Pressure Regulator. Cheep and easy to replace but I think the
fuel filter is more prevalent problem.

7) Remove + battery and unplug MAS sensor. If the MAS is bad then
unpluging it will cause the computer to go to a generic setting. Might have
to start your truck twice to keep it running. The MAS is a sensitive device
that can be ruined if you leave the battery connected. If the MAS sensor
is bad then after starting the truck for the second time the truck should
run fine.

Cool Reset the computer by removing + battery cable for 30 min.

After all this then go to the gaskets. Reason being is that usually only one
side will go bad first. Just does not make sence not at least till 70K.
Usually when these start going bad the symptoms start slowly. For Eg
slightly eradic idle. Bizar highway crusing performance. Full throttle
acceleration is OK because low vacumme.
Expert:  Geordie replied 7 years ago.


Thankyou, theres some good stuff in there. We would have gotten to the EGR valve etc if we had carried on.

The best of luck with the repair, I hope you get there without too much hassle.

Very best regards


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... seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like
...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 P Elm City, NC
< Previous | Next >
  • 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 P Elm 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. Phil Marysville, 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. Charles Walnut 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!
    Sue Charleston, WV
  • Another great insight to what may be the problem. I will have my mechanic take a look at it tomorrow. Thanks again, do indeed know your stuff. Jim Castleberry, FL
  • Excellent reply, and also very quick. Really sounds like the Expert knows what he is talking about. I will be back to use your service when I need more help with my RV. Dutch USA

Meet The Experts:

  • Chris (aka-Moose)

    Chris (aka-Moose)


    Satisfied Customers:

    16 years of experience
< Last | Next >
  • Chris (aka-Moose)'s Avatar

    Chris (aka-Moose)


    Satisfied Customers:

    16 years of experience
  • Ted G.'s Avatar

    Ted G.

    ASE Certified Technician

    Satisfied Customers:

    20 years auto repair experience, ASE Master Tech, Mechanical Failure consultant, Expert Witness
  • George H.'s Avatar

    George H.

    ASE Certified Technician

    Satisfied Customers:

    ASE Master Tech 15+ yrs, AAS Automotive Technology, Factory trained Asian specialist
  • GM Tech (Cam)'s Avatar

    GM Tech (Cam)

    Auto Service Tech

    Satisfied Customers:

    GM Grand Master Technician 2007. 14 years experience.
  • Amedee's Avatar


    ASE Master Tech

    Satisfied Customers:

    ASE Master Tech advanced level specialist. Wisconsin certified emissions state inspector
  • Jerry's Avatar


    Master Mechanic

    Satisfied Customers:

    ASE master, 30+ years. All makes and models. Trouble shooter, shop forman, service manager
  • Richard's Avatar


    ASE Certified Technician

    Satisfied Customers:

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