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 Greg Your Own Question
Greg, Technician
Category: Jeep
Satisfied Customers: 6732
Experience:  maintain jeep wrangler's for a off road rental company,
Type Your Jeep Question Here...
Greg is online now
A new question is answered every 9 seconds

1996 Jeep Grand Cherokee Laredo: 6cyl 4.0..recently replaced..muffler

Resolved Question:

I have a 1996 Jeep Grand Cherokee Laredo 6cyl 4.0 with poor engine performance. I recently replaced a bad Cat converter and muffler. I'm currently getting the codes 12 - 43 - 37 - 21 - 45 - 22 - 55
I looked up the codes but that doesn't help on what to fix.
Submitted: 4 years ago.
Category: Jeep
Expert:  Greg replied 4 years ago.
Name is XXXXX XXXXX i will assist you the best i can, please Only accept if you are happy with my answer.

Is the car drivable , as i would like you to take a drive down to AutoZone and get a free code read out done , as your jeep is OBDII .

As soon as you have the codes please post them here for me.

Kind regards Greg
Customer: replied 4 years ago.
Ok here's the codes autozone pulled, P1762 - P1757 - P0138 - P0141 - P0300 - P0304 - P0118
The truck runs though lacks power when going from a stop. Sometimes usually when engine is cold it will not leave the lower gears ( its a automatic) and the engine will just race. Stopping and shifting through the gears, park to low 1 back and forth a few times corrects it.
Hope this helps.
Customer: replied 4 years ago.
Also just found the ccv/pcv vacuum house the one towards the cabin rotted at the connector it was just placed in it.
Expert:  Greg replied 4 years ago.
Hi .

Thanks you for the codes this will make it a lot easier to start repairs for your issue .

First we have to repair the P)300 P0304
Which means you have a multiply misfire and a main misfire on cylinder # XXXXX

So we have to start with the basics ,
Spark plugs ,wires etc , this you have done so this is a good start ,but you still have a problem .

Next what has to be done is check the fuel pressure ,

If the fuel pressure is good then we have to check the injectors ,

Easiest whey to do this is remove the #4 injector and swap it over with the # XXXXX .
clear the codes then run the engine and see if the code changes to #6,(P0306) if this is the case you have a bad injector and this will have to be replaced .

Then you have the codes:

P1757 - Governor Pressure Above 3 PSI When Request Is 0 PSI

P1762 - Governor Pressure Sensor Offset Improper Voltage

These are transmission issue and both codes are pointing towards the governor pressure sensor; in most cases this part has to be replaced but best checked first with the diagnostic scan tool just to be safe and not end up replacing parts not needed .

P0138 - P0141 These are your down stream sensors on the exhaust which is probably a bad sensor or a wiring issue short to ground or short to voltage . So this system will have to be checked out .

P0118 is a ect issue meaning a coolant sensor malfunction or a wiring issue .

To be honest you need a good diagnostic scan tool to check these issue out otherwise you will end up just replacing parts with nor good results and spend a fortune for nothing .

So my advise for the problem you have is to take it to a known good shop that works on Jeeps to have this checked out for you. or visit the Jeep dealer .

But if you have a diagnostic tool i would be more than happy to walk you though this repair .

Kindest regards Greg.
Greg, Technician
Category: Jeep
Satisfied Customers: 6732
Experience: maintain jeep wrangler's for a off road rental company,
Greg and 2 other Jeep Specialists are ready to help you

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:

  • Thank you so much for your answer. My initial estimate was $325; I got it done for $100 - part and labor. Lynn B. Ormond Beach, FL
< Previous | Next >
  • Thank you so much for your answer. My initial estimate was $325; I got it done for $100 - part and labor. Lynn B. Ormond Beach, FL
  • I was skeptical at first but thought I'd give it a try. I was pleasantly surprised. Your site actually is a quality service that I would recommend to others in a heartbeat. Stan Sayre, PA
  • 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!!!! Alex Los 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. GP Hesperia, CA
  • I couldn't be more satisfied! This is the site I will always come to when I need a second opinion. Justin Kernersville, 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. Esther Woodstock, NY

Meet The Experts:

  • Chris


    Shop Foreman

    Satisfied Customers:

    Jeep Certified Master Tech
< Last | Next >
  • Chris's Avatar


    Shop Foreman

    Satisfied Customers:

    Jeep Certified Master Tech
  • Mark's Avatar


    22 Year Factory trained technician

    Satisfied Customers:

    Jeep factory training........25 years in the industry.
  • Dave's Avatar


    Jeep Master Tech

    Satisfied Customers:

    Chrysler Triple Master, ASE master Tech AA degree in Auto.
  • moparfl's Avatar


    ASE Certified Technician

    Satisfied Customers:

    ASE Master Tech Chrysler Dodge Jeep Master Tech
  • Tim Mohr's Avatar

    Tim Mohr


    Satisfied Customers:

  • Ron Z.'s Avatar

    Ron Z.

    - Jeep Tech -

    Satisfied Customers:

    18+yrs experience. State Inspector & Jeep Diagnostics/Repair
  • jeepmopar76's Avatar


    Jeep/Chrysler Triple Master Tech

    Satisfied Customers:

    32yr ASE Master Tech, 9yr Chrysler Master Tech, 19 yr Jeep Dealership service including AMC/Eagle